Fertilisation of Orchids
Encyclopedia
Fertilisation of Orchids is a book by Charles Darwin
published on 15 May 1862 under the full explanatory title On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. Darwin's previous book, On the Origin of Species, had briefly mentioned evolutionary interactions between insects and the plants they fertilised, and this new idea was explored in detail. Field studies and practical scientific investigations that were initially a recreation for Darwin, a relief from the drudgery of writing, developed into enjoyable and challenging experiment
s. Aided in his work by his family, friends, and a wide circle of correspondents across Britain and worldwide, Darwin tapped into a contemporary vogue for growing exotic orchids.
The book was his first detailed demonstration of the power of natural selection
, and explained how complex ecological
relationships resulted in the coevolution of orchid
s and insects. The view has been expressed that the book led directly or indirectly to all modern work on coevolution and the evolution of extreme specialisation. It influenced botanist
s, and revived interest in the neglected idea that insects played a part in pollinating
flowers. It opened up the new study areas of pollination research and reproductive ecology, directly related to Darwin's ideas on evolution
, and supported his view that natural selection led to a variety of forms through the important benefits achieved by cross-fertilisation
. Although the general public showed less interest and sales of the book were low, it established Darwin as a leading botanist. Orchids was the first in a series of books on his innovative investigations into plants.
The book describes how the relationship between insects and plants resulted in the beautiful and complex forms which natural theology
attributed to a grand designer
. By showing how practical adaptations develop from cumulative minor variations of parts of the flowers to suit new purposes, Darwin countered the prevailing view that beautiful organisms were the handiwork of a Creator
. Darwin's painstaking observations, experiments, and detailed dissection of the flowers, explained previously unknown features, such as the puzzle of Catasetum
which had been thought to have three completely different species of flowers on the same plant, and produced testable predictions. His proposal that the long nectary of Angraecum sesquipedale
meant that there must be a moth with an equally long proboscis
was controversial at the time, but was confirmed in 1903 when Xanthopan morgani praedicta
was found in Madagascar
.
grew up with an interest in natural history
, and as a student at the University of Cambridge
he became a pupil and close friend of botany
professor John Stevens Henslow
. The year he graduated, Darwin was given a position as a gentleman naturalist and geologist
on the second voyage of HMS Beagle
, a trip that lasted five years. By the time he returned in October 1836, he had doubts about the doctrine that species
were fixed and unchanging. Within months, experts informed him that specimens he had collected were separate species, not just varieties, and the patterns he saw inspired the inception of his theory
of natural selection
in 1838. Darwin began editing and publishing the expert reports, collected in the Zoology of the Voyage of H.M.S. Beagle
, at the same time as writing a series of books on geology, the first of which was The Structure and Distribution of Coral Reefs
. His "species work" was his "prime hobby", a background to this writing, but it evolved into an extensive research programme during the twenty years before he published his theory
.
played an important role in keeping specific forms consistent. He rejected the doctrine that the characteristics of a species were static, and was aware from animal husbandry
that inbreeding
could lead to changes, often deleterious. He thought that natural outbreeding
through cross-fertilisation would keep wild species homogenous yet vigorous. Cross-fertilisation would confer an evolutionary advantage
by spreading favourable changes throughout a reproductive community. His ideas were contrary to the common supposition that plants were usually self-fertilising, and so every summer Darwin investigated the contribution of insect pollination
to the cross-pollination
of flower
s.
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In the summer of 1841 Charles and Emma Darwin
moved from the turmoil of London
to the countryside, to Down House
, a quiet former parson
age in the village of Downe
. He wrote, "The flowers are here very beautiful". Darwin followed the recommendation of his friend, the leading botanist Robert Brown
, and read Das entdeckte Geheimnis der Natur im Bau und in der Befruchtung der Blumen
(The Secret of Nature in the Form and Fertilisation of Flowers Discovered). The little known book, published in 1793 by Christian Konrad Sprengel
but never translated into English, introduced the idea that flowers were created by God to fulfill a teleological purpose
: insects would act as "living brushes" to cross-fertilise plants in a symbiotic
relationship. This functional view was rejected and mostly forgotten, as it contradicted the common belief that flowers had been created for beauty, and were generally self-fertilising. For Darwin, the concept of evolution
gave new meaning to Sprengel's research into the mechanisms for cross-fertilisation. He welcomed its support for his supposition that cross-fertilisation in flowering plants tended to allow their offspring to avoid possible disadvantages resulting from self-fertilisation, and by 1845 he had verified many of Sprengel's observations.
A favourite walk took the Darwin family to a spot above the quiet Cudham
valley, teeming with orchids including Cephalanthera
, Neottia, fly orchids
and musk orchids
. They called this place "Orchis Bank", and the whole family became involved in Darwin's researches. Darwin observed orchids every summer, but in twenty years, only on two occasions (when he noticed butterflies "sucking O. pyramidalis
and Gymnadenia
") did he see insects visiting flowers.
In 1854, Darwin began to work full-time on the origin of species. He examined orchids and counted how often one or both pollinia
(pollen masses) had been removed from their flowers, indicating that they had been visited by insects. He experimented with insect pollination to investigate whether, by cross-fertilising field crops such as Fabaceae
, they would yield more vigorous offspring, and published letters about his inconclusive results in The Gardeners' Chronicle in 1857 and 1858. He next applied Sprengel's methods to empirical research
on orchids. Despite delays caused by recurring illness
, he made progress on writing his planned "Big Book" on evolution, but when Alfred Russel Wallace
's letter prompted joint publication of both of their theories of natural selection
in 1858, Darwin quickly wrote On the Origin of Species as an abstract of his theory, published on 22 November 1859. In this book, he gave credence to Sprengel's ideas on the advantages of "intercrossing", and noted: "Many of our orchidaceous plants absolutely require the visits of moths to remove their pollen masses and thus to fertilise them". He introduced his new concept, the process of coevolution, describing the co–adaptation
of bumblebee
s and red clover, and speculating "how a flower and a bee might slowly become, either simultaneously or one after the other, modified and adapted in the most perfect manner to each other, by the continued preservation of individuals presenting mutual and slightly favourable deviations of structure." This was a theme he developed in his orchid book.
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After On the Origin of Species was published, Darwin became involved in producing revised editions as well as working on Variation of Animals and Plants Under Domestication as the first part of his planned "Big Book".
By the spring of 1860 he had tired of the grind of writing, and needed something fresh and interesting to study. During a family visit to relatives at Hartfield
, he was searching for orchids when he noticed a sundew. He collected it and tried to feed it insects, thus beginning a long-term study of insectivorous plants
. He investigated other botanical
questions raised by his ideas of natural selection
, including the advantages of sexual dimorphism
in primula
s, and the adaptive mechanisms
that ensure cross-pollination in orchids. As an enthusiastic practical scientist, such investigations gave him a strong sense of personal enjoyment. He relished pitting his wits against nature, and following lucky hunches
. His theory was a way of looking at the world, enabling him to find creative solutions to problems that traditional approaches could not solve. He later wrote, "I am like a gambler, & love a wild experiment."
Around the end of April 1860, Darwin discussed insect pollination with his friend Joseph Dalton Hooker
, and mentioned the bee orchid
. Darwin corresponded with Hooker's assistant Daniel Oliver
, the senior curator at Kew Gardens, who became a follower of Darwin's ideas. At the start of June, Darwin wrote to The Gardeners' Chronicle
asking for readers' observations on how bee or fly orchids
were fertilised. His letter described the mechanisms for insect fertilisation he had discovered in common British orchids, and reported his experimental observations that pollen masses were removed from Orchis morio
and Orchis mascula plants in the open, but left in their pouches in adjacent plants under a glass bell jar
. He wrote to American botanist Asa Gray
that he had been "so struck with admiration at the contrivances, that I have sent notice to Gardeners Chronicle", and made similar enquiries of other experts.
Darwin became engrossed in meticulous microscopic examination, tracing the complicated mechanisms of flowers that attracted insects by their nectar so that the insects transported pollen to cross-pollinate other plants, and on 19 July he told Hooker, "I am intensely interested on subject, just as at a game of chess." In September, he "dissected with the greatest interest" and wrote, "The contrivances for insect fertilisation in Orchids are multiform & truly wonderful & beautiful." By October, he had "a large mass of notes with many new facts", but set them aside "convinced that I ought to work on Variation & not amuse myself with interludes".
During 1861, botany became a preoccupation for Darwin, and his projects became serious scientific pursuits. He continued his study of orchids throughout the summer, writing to anyone who might be able to supply specimens he had not yet examined. Field naturalists, botanists, and country gentry
sent specimens from across the British Isles. Darwin also tramped around the countryside with tin cans and biscuit boxes, collecting specimens which his gardeners potted up for him. His family joined in, and neighbours contributed to the research. As he had only a cold greenhouse
, a friend on the other side of the village who had a hot-house allowed him to use that, and offered the services of his gardener to look after the delicate specimens. Darwin's aim was to show how the complex structures and life cycles of the plants could be explained by natural selection rather than by the handiwork of God; he saw the huge variety of flowers as a collection of ad hoc
evolutionary adaptations. In June he described his examination of bee orchids
as a passion, and his findings on insect fertilisation of orchids as "beautiful facts".
There were several replies to Darwin's enquiry in The Gardeners' Chronicle
seeking evidence to support his idea that pollen masses attached themselves to a convenient place on an insect's back or head, usually its proboscis
, to transport the pollen to another flower. One envelope appeared to be empty when it arrived at Down House, but when he looked further before discarding it he found several insect mouthparts with pollen masses attached. To help their daughter Henrietta
convalesce from illness, the Darwins arranged to spend two months in Torquay
. Darwin wrote:
He sought advice on obtaining the exotic South America
n Catasetum
, to see it eject pollen masses, as "I am got intensely interested on subject & think I understand pretty well all the British species." They went to Torquay on 1 July, and Darwin began writing his Orchid paper. By 10 August, he feared his paper would run "to 100 M.S. folio pages!!! The beauty of the adaptations of parts seems to me unparalleled ... I marvel often as I think over the diversity & perfection of the contrivances."
The family returned to Downe on 27 August, and Darwin again wrote to the Gardeners' Chronicle appealing for assistance as he was "very anxious to examine a few exotic forms." His requests to the wealthy enthusiasts who had taken up the fashionable pursuit of growing rare orchids brought large numbers of specimens. These would be a test of his theory: previously aspects such as coloration of plants and animals had often been regarded as having no adaptive function. For example, Thomas Henry Huxley was strongly influenced by German idealism
and in 1856 had asked if it was "to be supposed for a moment that the beauty of colour and outline ... are any good to the animals? ... Who has ever dreamed of finding an utilitarian purpose in the forms and colours of flowers ... ?" Darwin had, and in the orchids he tackled the most difficult case. His ideas would transform the way naturalists thought about coloration.
The completed Orchis paper came to 140 folio pages, and Darwin decided against presenting it at the Linnean Society of London
, thinking of publishing a pamphlet instead. He offered the draft to John Murray
who agreed to publish it as a book. Although Darwin feared a lack of public interest, he hoped it would serve to "illustrate how Natural History may be worked under the belief of the modification of Species." In discussions with Asa Gray about natural theology
, he wrote that "it really seems to me incredibly monstrous to look at an orchid as created as we now see it. Every part reveals modification on modification."
As a popular and acceptable activity, botany had been taken up by many middle class ladies, and Darwin included these botany enthusiasts in his correspondence. On the recommendation of John Lindley
, Darwin wrote to Lady Dorothy Nevill
, who responded generously by sending numerous exotic orchids, and requested a signed photograph of him to hang in her sitting room next to portraits of her other notable friends, including Hooker.
of the Angraecum sesquipedale
flowers, one of the orchids sent by the distinguished horticulturist James Bateman
, and wrote to Hooker "Good Heavens what insect can suck it[?]"
By November, a specimen of the exotic South America
n Catasetum
orchid Hooker had given to Darwin had shown its "truly marvellous" mechanism, by which it shot out a pollinium
at any insect touching a part of the flower "with sticky gland always foremost". This plant had astonished botanists in 1836 when Robert Hermann Schomburgk
stated that he had seen one plant growing three distinct flowers which usually grew separately and had wrongly been categorised as three distinct genera
, namely Catasetum tridentatum, Monachanthus viridis, and Myanthus barbatus. John Lindley
had remarked that "such cases shake to the foundation all our ideas of the stability of genera and species." One of Darwin's correspondents told of delight at growing a beautiful specimen of Myanthus barbatus imported from Demerara
, then dismay when the plant flowered the next year as a simple Catasetum.
In view of this interest, Darwin prepared a paper on Catasetum as an extract from his forthcoming book, which was read to the Linnean Society of London
on 3 April 1862. Darwin solved the puzzle by showing that the three flowers were the male, female, and hermaphrodite forms of a single species, but as they differed so much from each other, they had been classified as different genera.
on 9 February 1862, while he was still working on the last chapter. Although anxious that the book might not sell, he could "say with confidence that the M.S. contains many new & very curious facts & conclusions". When the book was printed, he sent out presentation copies to all the individuals and societies who had helped him with his investigations, and to eminent botanists in Britain and abroad for review.
On 15 May 1862 the book was published under the full title of On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. In August, Darwin was "well contented with the sale of 768 copies; I shd. hope & expect that the remainder will ultimately be sold", but the book sold slowly and less than 2,000 copies of the first edition were printed. An expanded edition translated into French was published in Paris in 1870, and in 1877 Murray brought out a revised and expanded second edition, with the shortened title The various contrivances by which orchids are fertilised by insects. This was also published by D. Appleton & Company
of New York in 1877, and a German translation was published in the same year. Despite being well praised by botanists, only about 6,000 copies of the English editions had been sold by 1900.
by expanding on the theme of coevolution between local populations of insects and flowering plants that he had briefly discussed in On the Origin of Species. He examined numerous ways in which orchids vary, showing how they had diverged and developed specialised pollen-dispersal mechanisms. The intricate morphology
and anatomy
of each flower was carefully described. Apparently trivial details were examined in relation to natural selection
to demonstrate how slight variations in similar structures
of closely related flowers led to specialised modifications that provided various pollinators (insects) with different ways to cross-fertilise. The mass of descriptive detail was a great achievement, but the result is demanding to read.
In the introduction, Darwin explained his aim of meeting complaints that detailed support for his theory was lacking in On the Origin of Species. He chose orchids for his subject as "amongst the most singular and most modified forms in the vegetable kingdom" in the hope of inspiring work on other species, and felt that "the study of organic beings may be as interesting to an observer who is fully convinced that the structure of each is due to secondary laws, as to one who views every trifling detail of structure as the result of the direct interposition of the Creator." He gave due credit to previous authors who had described the agency of insects in fertilising orchids, and all who had helped him.
In the first chapter Darwin described the British orchids he had studied, giving detailed explanations of their various mechanisms for transferring pollen to insects.
The first mechanism described is that of Orchis mascula, which serves as an introduction to the explanation of other Orchidaceae
. In the upper part of the flower a petal shelters the male organ
which has two packages of pollen grains, held together by thin elastic threads. These pollen masses
stand side by side and have stalks down to adhesive balls in a cup which keeps them moist and sticky. When an insect lands on the large projecting lower petal, the labellum
, and pushes its head and proboscis
into the centre of the flower and down to the nectary, it breaks the cup and the adhesive balls attach the pollen masses to the front of the insect. As the insect flies off, each stalk rotates the pollen mass downwards and forwards so that when the insect lands on another flower the pollen masses attached to the insect pass under the male organ and leave pollen on the female organ
, achieving cross fertilisation. Darwin envisaged:
This is followed by descriptions of the differences in the mechanisms of several other orchids. In Orchis pyramidalis
, the adhesive balls are combined together into a strap or saddle shape, which curls round the thin proboscis
of a moth or butterfly to attach to it the pair of pollen masses, illustrated in the book by figure 4 showing a moth's head with seven pairs of pollen masses attached to its proboscis.
While the bee orchid
showed adaptation
for self-fertilisation, its mechanism also enabled occasional cross-fertilisation, creating the biological diversity
that Darwin felt was needed for vigorous survival, which could not be provided by self-fertilisation. As an example of "how beautifully everything is contrived", Darwin described how he had found that in Spiranthes
flowers the pollen is ready for collection before access is open for the female organ to receive pollen. At Torquay
he had watched bees visiting spires of these flowers, starting at the bottom of the spire and working their way up to the topmost flowers. He speculated that if bees moved from top to top of the spires, the pollen clusters they collected from the most recently opened flowers would be wasted as the topmost flowers on the next spike would not be ready to receive pollen. A bee starting at the lowest flowers on the first spire it visited would continue up until it reached flowers that still had their pollen masses to attach to the bee, then would fly to the mature lower flowers on another plant, and fertilise them. By this co-ordinated process, the bee would add "to her store of honey" while perpetuating the flowers "which will yield honey to future generations of bees".
The book moves on to the various foreign orchids Darwin had received from others. His experiments showed that the "astonishing length" of the 11 inch (290 mm) long nectary hanging from Angraecum sesquipedale
flowers implied the need for an as yet unknown moth with a proboscis
10–11 inches (250–275 mm) long to pollinate these flowers in Madagascar
. He viewed this as the outcome of a coevolutionary race, writing that "there has been a race in gaining length between the nectary of the Angræcum and the proboscis of certain moths". This wastefulness is familiar in modern terms as the idea of an evolutionary arms race
, but was disturbing to biologists of the time who believed that adaptations were the outcome of benevolent divine purpose
.
Darwin described "the most remarkable of all Orchids", Catasetum
, and showed how in these flowers, "as throughout nature, pre-existing structures and capacities [had been] utilised for new purposes". He explained the mechanism in which the pollen masses of the pollinium
were connected by a bent stalk or pedicel
to a sticky disc kept moist at the back of the flower. When an insect touched an "antenna" projecting from the back of the flower, this released the bent pedicel which sprang straight and fired the pollinium, sticky disc first, at the insect. In experiments, Darwin had imitated this action using a whalebone spring. He vividly illustrated how the flower ejected the pollinium with considerable force: "I touched the antennæ of C. callosum whilst holding the flower at about a yard's distance from the window, and the pollinium hit the pane of glass, and adhered to the smooth vertical surface by its adhesive disc."
to attract insects, seemed also in some cases to act as an excretion
: "It is in perfect accordance with the scheme of nature, as worked out by natural selection, that matter excreted to free the system from superfluous or injuring substances should be utilised for purposes of the highest importance." Homologies
of the orchid flowers of orchids showed them all to be based on "fifteen groups of vessels, arranged three within three, in alternating order". He disparaged the idea that this was an "ideal type" fixed by the Omnipotent Creator, but attributed it instead to its "descent from some monocotyledon
ous plant, which, like so many other plants of the same division, possessed fifteen organs, arranged alternately three within three in five whorls; and that the now wonderfully changed structure of the flower is due to a long course of slow modification,—each modification having been preserved which was useful to each plant, during the incessant changes to which the organic and the inorganic world has been exposed".
Describing the final end state of the whole flower cycle as the production of seed, he set out a simple experiment in which he took a ripe seed capsule and arranged the seeds in a line, then counted the seeds in one-tenth of an inch (2.5 mm). By multiplication he found that each plant produced enough seeds to plant 1 acres (4,046.9 m²) of ground, and the great grandchildren of a single plant could "carpet the entire surface of the land throughout the globe" if unchecked.
In conclusion, he felt that the book had "shown that Orchids exhibit an almost endless diversity of beautiful adaptations. When this or that part has been spoken of as contrived for some special purpose, it must not be supposed that it was originally always formed for this sole purpose. The regular course of events seems to be, that a part which originally served for one purpose, by slow changes becomes adapted for widely different purposes."
He was almost exasperated by the inventiveness of forms in nature; "In my examination of Orchids, hardly any fact has so much struck me as the endless diversity of structure,—the prodigality of resources,—for gaining the very same end, namely, the fertilisation of one flower by the pollen of another." His focus on detail was justified, as "The use of each trifling detail of structure is far from a barren search to those who believe in natural selection." The "contrivances and beautiful adaptations" slowly acquired through slight variations, subjected to natural selection "under the complex and ever-varying conditions of life", far transcended the most fertile imagination. The mechanisms to transport the pollen of one flower or of one plant to another flower or plant underlined the importance of cross-fertilisation: "For may we not further infer as probable, in accordance with the belief of the vast majority of the breeders of our domestic productions, that marriage between near relatives is likewise in some way injurious,—that some unknown great good is derived from the union of individuals which have been kept distinct for many generations?"
Botanists responded favourably to the book immediately on its publication. Hooker told Darwin that the book showed him to be "out of sight the best Physiological observer & experimenter that Botany ever saw", and was glad to note that two leading traditional botanists had accepted the concept of evolution; "Bentham & Oliver are quite struck up in a heap with your book & delighted beyond expression". Daniel Oliver
thought it "very extraordinary", and even Darwin's old beetle-hunting rival Charles Babington
, by then professor of botany at the University of Cambridge
and inclined to oppose natural selection, called it "exceedingly interesting and valuable ... highly satisfactory in all respects. The results are most curious and the skill shown in discovering them equally so." George Bentham
praised its value in opening "a new field for observing the wonderful provisions of Nature ... a new and unexpected track to guide us in the explanation of phenomena which had before that appeared so irreconcilable with the ordinary prevision and method shown in the organised world."
The book's success in botanical circles was enhanced following Bentham's public endorsement. In his presidential address to the Linnean Society
on 24 May 1862, Bentham praised the book as exemplifying the biological method, and said that it had nearly overcome his opposition to the Origin. In his address in 1863 he stated that "Mr Darwin has shown how changes may take place", and described it as "an unimpeachable example of a legitimate hypothesis" in compliance with John Stuart Mill
's scientific method
. This endorsement favourably influenced Miles Joseph Berkeley
, Charles Victor Naudin
, Alphonse Pyramus de Candolle, Jean Louis Quatrefages
, and Charles Daubeny
.
In June 1862, Darwin welcomed favourable reviews in the press and wrote to Hooker; "Well my orchis-book is a success (but I do not know whether it sells) after cursing my folly in writing it". He told his publisher, "The Botanists praise my Orchid-book to the skies", and to Asa Gray
he said, "I am fairly astonished at the success of my book with botanists." Darwin's geologist friend Charles Lyell
gave it enthusiastic praise: "next to the Origin, as the most valuable of all Darwin's works." However, the book attracted little attention from the general public, and in September Darwin told his cousin Fox
, "Hardly any one not a botanist, except yourself, as far as I know, has cared for it." The book baffled a general public more interested in controversy over gorillas and cavemen. There were some reviews in gardening magazines, but few natural philosophers or zoologists noticed the book, and hardly any learned appraisals appeared.
Although the book contradicted the prevailing natural theology
and its teleological
approach to design in nature, the Saturday Review
thought that it would avoid the angry polemics aroused by On the Origin of Species. The Literary Churchman welcomed "Mr. Darwin's expression of admiration at the contrivances in orchids", only complaining that it was too indirect a way of saying "O Lord, how manifold are Thy works!" (Psalm
104:24
) Darwin regarded these theological views as irritating misunderstandings, but wrote to Asa Gray
describing his approach as a "flank movement on the enemy". By showing that the "wonderful contrivances" of the orchid have discoverable evolutionary histories, Darwin was countering claims by natural theologians that the organisms were examples of the perfect work of the Creator.
There was considerable controversy surrounding Darwin's prediction that a moth would be found in Madagascar
with a long proboscis matching the nectary of Angraecum sesquipedale
. An anonymous article in the Edinburgh Review
of October 1862 by George Campbell, 8th Duke of Argyll
, argued that Darwin's wording implied purpose, and concluded that "We know, too, that these purposes and ideas are not our own, but the ideas and purposes of Another." He considered Darwin's explanations the "most unsatisfactory conjectures", and raised obscure metaphysical objections while supporting a kind of creative evolutionism. Emma Darwin thought that although Argyll was "quite opposed" to Darwin's views, "he praises the Orchids in such an enthusiastic way that he will do it a good turn". Darwin was delighted to find that a well written article "smashing" Argyll's review was by one of Darwin's own nephews.
Argyll went on in his 1867 book The Reign of Law to cleverly ridicule Darwin's ideas, particularly the prediction of a moth in Madagascar with a proboscis 10–11 inches (250–275 mm) long. He believed that adaptations showed divine purpose, not a mindless evolutionary arms race
. In his response Creation by Law later that year, Alfred Russel Wallace
produced a detailed explanation of how the nectary could have evolved through natural selection, and stated that he had carefully measured moths in the British Museum
, finding that the proboscis of Macrosila cluentius
from South America was 9 inches (235 mm) long, and the proboscis of Macrosila morganii from tropical Africa (since renamed Xanthopan morgani
) was 7 inches (190 mm) long. An enquiry raised in 1873 was answered by Darwin's friend Hermann Müller
, who stated that his brother Fritz Müller
had caught a sphinx moth in Brazil
with a proboscis nearly 10 inches (254 mm) long. Darwin's anticipation was fully met in 1903, when a subspecies of Xanthopan morgani was found in Madagascar with a proboscis about 12 inches (300 mm) long, and was named Xanthopan morgani praedicta to celebrate this verification of a testable prediction made by Darwin on the basis of his theory of natural selection
.
has expressed the view that all studies of coevolution follow directly or indirectly from Darwin's orchid book, which was also the origin of all work on the evolution of extreme specialisation. Its publication led almost immediately to research by many other naturalists into specialisation and coevolution, in some cases analysing other taxa
. In his autobiography
, Darwin modestly recalled how this work had revived interest in Christian Konrad Sprengel
's neglected ideas:
Among the many prominent biologists who began research on coevolution, Hermann Müller
was particularly interested in the evolutionary sequence in which insects and flowers became adapted to each other. Like Darwin, he began with the premise that flowers were adapted to ensure cross-fertilisation, and added his own premise that most insects were not "limited by hereditary instinct to particular flowers". On this basis, he developed the view that specialisation develops from the need for flowers to attract pollinating insects (without making access too easy for non-pollinators), and from the evolution of pollinators to adapt to changes in the location of rewards such as nectar. He found that Alpine flowers
tended to be visited by bees at lower altitudes, and by butterflies at higher altitudes, beginning research on the idea that plants at different altitudes were specialised for different pollinators. By comparing related plant species that he thought had diverged in form from a common ancestor, and testing whether they were visited by butterflies or bees, he was the first to use a combination of morphological
and ecological
approaches to understand patterns in the evolution of interactions and specialisation. His brother Fritz Müller
used similar methods when studying mimicry in Brazil. The early development of ideas on specialisation and coevolution became increasingly focused on the problem of mimicry; Henry Walter Bates
had initially raised this issue in a paper read to the Linnean Society of London
in December 1861 in Darwin's presence, and published in November 1862.
Others basing their studies of reproductive ecology on Darwin's evolutionary approach included Friedrich Hildebrand and Severin Axell in Europe, Asa Gray
and Charles Robertson in North America. In Italy, Federigo Delpino adopted the theory of descent but like Sprengel had a teleological
approach and explained the mechanisms of flowers by the intervention of a "psychovitalistic intelligence". Delpino classified flowers on the basis of the pollinators they attracted, and coined many of the terms still in use such as pollination syndrome
and ornithophily
. There was an enormous increase in knowledge during this period. In 1874, Asa Gray paid tribute to Darwin's work on orchids for explaining "all these and other extraordinary structures, as well as of the arrangement of blossoms in general, and even the very meaning and need of sexual propagation". He credited Darwin with establishing the understanding that "Nature abhors close fertilization".
By the end of the 19th century, there were so many uncritical and unproven speculations about floral mechanisms that floral ecology became discredited. In the 1920s, it was revived with further developments in detailed analyses of insects' senses, led by researchers Frederic Clements
, Karl von Frisch
and others. Their experiments resulted in new information, including the discovery that some insect
s have ultraviolet
vision, and findings involving bee learning and communication
. Modern floral ecology has been reinvigorated by its relevance for evolutionary studies.
Darwin had "found the study of orchids eminently useful in showing me how nearly all parts of the flower are coadapted for fertilisation by insects, & therefore the result of n. selection,—even most trifling details of structure". His own interest in orchids and in fertilisation of plants by insects continued. Darwin had been given the use of a hot-house at The Rookery on the other side of the village, and at the end of 1862 he was persuaded by this neighbour's helpful gardener to have his own built at Down House as an extension to the existing cold lean-to greenhouse
. The gardener drew up plans, and Darwin investigated stoves and ventilation devices. When it was completed in February 1863 he asked Hooker for some plants from Kew Gardens, writing "I long to stock it, just like a school-boy", and sent his butler with a cart. When over 160 different plants were delivered, Darwin made apologetic remarks about depleting the national collection. He told Hooker "You cannot imagine what pleasure your plants give me ... Henrietta & I go & gloat over them." Darwin's life was changed by having a warm hothouse to spend time in before his walk round the Sandwalk, and in the 1870s he had several more hothouses built. The children later remembered this routine and the gardeners attending to Darwin's experimental plants, as well as the way that Darwin used simple equipment for his experiments, dissecting and measuring plants and seeds.
A chance observation "thoroughly aroused" Darwin's attention to a surprising decrease in vigour of the offspring of Linaria vulgaris
following only one instance of self-fertilisation, and after eleven years of experimental work he published The Effects of Cross and Self Fertilisation in the Vegetable Kingdom
in 1876 as "a complement to the 'Fertilisation of Orchids,' because it shows how important are the results of cross-fertilisation which are ensured by the mechanisms described in that book." He told a friend "I cannot endure doing nothing", and resumed his work on orchids, assisted in his research by his son Francis Darwin
. He corresponded about orchids with Fritz Müller
, and almost completely rewrote the book with a considerable amount of new material, much of which was contributed by Müller. The revised edition was published in 1877.
Francis Darwin described it as characteristic that his father delighted in the observations that preceded the publication of Fertilisation of Orchids, not the applause which followed it. He quoted one of his father's last letters about orchids, written in 1880:
manages Downe Bank
, which is near Down House and was a favourite place of the Darwin family, who called it 'Orchis Bank' because of the many wild orchids which grew there. It is now part of the 'Downe Bank and High Elms
' Site of Special Scientific Interest
. Darwin’s observations of local orchids and their insect pollinators gave him the evidence for co-evolution which provided the basis for the Fertilisation of Orchids." Experts have identified "Orchis Bank" as the species-rich setting encapsulated in the closing paragraph of On the Origin of Species, in which Darwin wrote:
Darwin's home and its surroundings, including specifically "Orchis Bank", have been called his landscape laboratory, and together were nominated in January 2009 for designation as a World Heritage Site
. The bid was made by a partnership led by the London Borough of Bromley
, which now includes Downe
. It was included in the 39 proposed properties, but was not in the 21 new sites selected for the list.
The influence of Darwin's work was commemorated in the Smithsonian Institution
's 15th Annual Orchid Show, Orchids Through Darwins Eyes, 24 January to 26 April 2009.
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
published on 15 May 1862 under the full explanatory title On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. Darwin's previous book, On the Origin of Species, had briefly mentioned evolutionary interactions between insects and the plants they fertilised, and this new idea was explored in detail. Field studies and practical scientific investigations that were initially a recreation for Darwin, a relief from the drudgery of writing, developed into enjoyable and challenging experiment
Experiment
An experiment is a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis. Experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results...
s. Aided in his work by his family, friends, and a wide circle of correspondents across Britain and worldwide, Darwin tapped into a contemporary vogue for growing exotic orchids.
The book was his first detailed demonstration of the power of natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
, and explained how complex ecological
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
relationships resulted in the coevolution of orchid
Orchidaceae
The Orchidaceae, commonly referred to as the orchid family, is a morphologically diverse and widespread family of monocots in the order Asparagales. Along with the Asteraceae, it is one of the two largest families of flowering plants, with between 21,950 and 26,049 currently accepted species,...
s and insects. The view has been expressed that the book led directly or indirectly to all modern work on coevolution and the evolution of extreme specialisation. It influenced botanist
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
s, and revived interest in the neglected idea that insects played a part in pollinating
Pollination
Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...
flowers. It opened up the new study areas of pollination research and reproductive ecology, directly related to Darwin's ideas on evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
, and supported his view that natural selection led to a variety of forms through the important benefits achieved by cross-fertilisation
Allogamy
Allogamy is a term used in the field of biological reproduction describing the fertilization of an ovum from one individual with the spermatozoa of another. By contrast, autogamy is the term used for self-fertilization. In humans, the fertilization event is an instance of allogamy...
. Although the general public showed less interest and sales of the book were low, it established Darwin as a leading botanist. Orchids was the first in a series of books on his innovative investigations into plants.
The book describes how the relationship between insects and plants resulted in the beautiful and complex forms which natural theology
Natural theology
Natural theology is a branch of theology based on reason and ordinary experience. Thus it is distinguished from revealed theology which is based on scripture and religious experiences of various kinds; and also from transcendental theology, theology from a priori reasoning.Marcus Terentius Varro ...
attributed to a grand designer
Deism
Deism in religious philosophy is the belief that reason and observation of the natural world, without the need for organized religion, can determine that the universe is the product of an all-powerful creator. According to deists, the creator does not intervene in human affairs or suspend the...
. By showing how practical adaptations develop from cumulative minor variations of parts of the flowers to suit new purposes, Darwin countered the prevailing view that beautiful organisms were the handiwork of a Creator
Creator deity
A creator deity is a deity responsible for the creation of the world . In monotheism, the single God is often also the creator deity, while polytheistic traditions may or may not have creator deities...
. Darwin's painstaking observations, experiments, and detailed dissection of the flowers, explained previously unknown features, such as the puzzle of Catasetum
Catasetum
Catasetum, abbreviated as Ctsm in horticultural trade, is a genus of the Orchid family , subfamily Epidendroideae, tribe Cymbidieae, subtribe Catasetinae, with 166 species....
which had been thought to have three completely different species of flowers on the same plant, and produced testable predictions. His proposal that the long nectary of Angraecum sesquipedale
Angraecum sesquipedale
Angraecum sesquipedale is an epiphytic orchid in the genus Angraecum that is endemic to Madagascar. The orchid was first discovered by the French botanist Louis-Marie Aubert du Petit-Thouars in 1798, but was not described until 1822...
meant that there must be a moth with an equally long proboscis
Proboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...
was controversial at the time, but was confirmed in 1903 when Xanthopan morgani praedicta
Xanthopan morgani
Xanthopan morgani, or Morgan's Sphinx, is a very large hawk moth from West Africa and Madagascar. It is the sole member of its genus, and little is known of the biology, though the adults have been found to visit orchids .In January 1862 while researching insect pollination of orchids, Charles...
was found in Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
.
Background
Charles DarwinCharles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
grew up with an interest in natural history
Natural history
Natural history is the scientific research of plants or animals, leaning more towards observational rather than experimental methods of study, and encompasses more research published in magazines than in academic journals. Grouped among the natural sciences, natural history is the systematic study...
, and as a student at the University of Cambridge
University of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...
he became a pupil and close friend of botany
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
professor John Stevens Henslow
John Stevens Henslow
John Stevens Henslow was an English clergyman, botanist and geologist. He is best remembered as friend and mentor to his pupil Charles Darwin.- Early life :...
. The year he graduated, Darwin was given a position as a gentleman naturalist and geologist
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
on the second voyage of HMS Beagle
Second voyage of HMS Beagle
The second voyage of HMS Beagle, from 27 December 1831 to 2 October 1836, was the second survey expedition of HMS Beagle, under captain Robert FitzRoy who had taken over command of the ship on its first voyage after her previous captain committed suicide...
, a trip that lasted five years. By the time he returned in October 1836, he had doubts about the doctrine that species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
were fixed and unchanging. Within months, experts informed him that specimens he had collected were separate species, not just varieties, and the patterns he saw inspired the inception of his theory
Inception of Darwin's theory
The inception of Darwin's theory occurred during an intensively busy period which began when Charles Darwin returned from the survey voyage of the Beagle, with his reputation as a fossil collector and geologist already established...
of natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
in 1838. Darwin began editing and publishing the expert reports, collected in the Zoology of the Voyage of H.M.S. Beagle
Zoology of the Voyage of H.M.S. Beagle
The Zoology of the Voyage of H.M.S. Beagle Under the Command of Captain Fitzroy, R.N., during the Years 1832 to 1836 is a 5-part book published unbound in nineteen numbers as they were ready, between February 1838 and October 1843...
, at the same time as writing a series of books on geology, the first of which was The Structure and Distribution of Coral Reefs
The Structure and Distribution of Coral Reefs
The Structure and Distribution of Coral Reefs, Being the first part of the geology of the voyage of the Beagle, under the command of Capt. Fitzroy, R.N. during the years 1832 to 1836, was published in 1842 as Charles Darwin's first monograph, and set out his theory of the formation of coral reefs...
. His "species work" was his "prime hobby", a background to this writing, but it evolved into an extensive research programme during the twenty years before he published his theory
Publication of Darwin's theory
The publication of Darwin's theory brought into the open Charles Darwin's ideas of evolution through natural selection, the culmination of more than twenty years of work....
.
Insect fertilisation of plants
Darwin's speculations on the origin of species convinced him that cross-fertilisationAllogamy
Allogamy is a term used in the field of biological reproduction describing the fertilization of an ovum from one individual with the spermatozoa of another. By contrast, autogamy is the term used for self-fertilization. In humans, the fertilization event is an instance of allogamy...
played an important role in keeping specific forms consistent. He rejected the doctrine that the characteristics of a species were static, and was aware from animal husbandry
Animal husbandry
Animal husbandry is the agricultural practice of breeding and raising livestock.- History :Animal husbandry has been practiced for thousands of years, since the first domestication of animals....
that inbreeding
Inbreeding
Inbreeding is the reproduction from the mating of two genetically related parents. Inbreeding results in increased homozygosity, which can increase the chances of offspring being affected by recessive or deleterious traits. This generally leads to a decreased fitness of a population, which is...
could lead to changes, often deleterious. He thought that natural outbreeding
Heterosis
Heterosis, or hybrid vigor, or outbreeding enhancement, is the improved or increased function of any biological quality in a hybrid offspring. The adjective derived from heterosis is heterotic....
through cross-fertilisation would keep wild species homogenous yet vigorous. Cross-fertilisation would confer an evolutionary advantage
Fitness (biology)
Fitness is a central idea in evolutionary theory. It can be defined either with respect to a genotype or to a phenotype in a given environment...
by spreading favourable changes throughout a reproductive community. His ideas were contrary to the common supposition that plants were usually self-fertilising, and so every summer Darwin investigated the contribution of insect pollination
Entomophily
Entomophily is a form of pollination whereby pollen is distributed by insects. Several insect are reported to be responsible for the pollination of many plant species, particularly bees, Lepidoptera , wasps, flies, ants and beetles. Some plant species co-evolved with a particular pollinator, such...
to the cross-pollination
Allogamy
Allogamy is a term used in the field of biological reproduction describing the fertilization of an ovum from one individual with the spermatozoa of another. By contrast, autogamy is the term used for self-fertilization. In humans, the fertilization event is an instance of allogamy...
of flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s.
Emma Darwin
Emma Darwin was the wife and first cousin of Charles Darwin, the English naturalist, scientist and author of On the Origin of Species...
moved from the turmoil of London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
to the countryside, to Down House
Down House
Down House is the former home of the English naturalist Charles Darwin and his family. It was in this house and garden that Darwin worked on his theories of evolution by natural selection which he had conceived in London before moving to Downe....
, a quiet former parson
Parson
In the pre-Reformation church, a parson was the priest of an independent parish church, that is, a parish church not under the control of a larger ecclesiastical or monastic organization...
age in the village of Downe
Downe
Downe is a village in the London Borough of Bromley in London, UK.Downe is south west of Orpington and south east of Charing Cross. Downe lies in a wooded valley, and much of the centre of the village is unchanged; the former village school now acts as the village hall.-Darwin:Charles Darwin...
. He wrote, "The flowers are here very beautiful". Darwin followed the recommendation of his friend, the leading botanist Robert Brown
Robert Brown (botanist)
Robert Brown was a Scottish botanist and palaeobotanist who made important contributions to botany largely through his pioneering use of the microscope...
, and read Das entdeckte Geheimnis der Natur im Bau und in der Befruchtung der Blumen
Das entdeckte Geheimnis der Natur im Bau und in der Befruchtung der Blumen
Das entdeckte Geheimnis der Natur im Bau und in der Befruchtung der Blumen, a little known book by Christian Konrad Sprengel on The Secret of Nature in the Form and Fertilisation of Flowers Discovered, was rejected by other naturalists when it was published in 1793, but was found to be of immense...
(The Secret of Nature in the Form and Fertilisation of Flowers Discovered). The little known book, published in 1793 by Christian Konrad Sprengel
Christian Konrad Sprengel
Christian Konrad Sprengel was a German theologist, teacher and, most importantly, a naturalist. He is most famously known for his research into plant sexuality....
but never translated into English, introduced the idea that flowers were created by God to fulfill a teleological purpose
Teleology
A teleology is any philosophical account which holds that final causes exist in nature, meaning that design and purpose analogous to that found in human actions are inherent also in the rest of nature. The word comes from the Greek τέλος, telos; root: τελε-, "end, purpose...
: insects would act as "living brushes" to cross-fertilise plants in a symbiotic
Symbiosis
Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...
relationship. This functional view was rejected and mostly forgotten, as it contradicted the common belief that flowers had been created for beauty, and were generally self-fertilising. For Darwin, the concept of evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
gave new meaning to Sprengel's research into the mechanisms for cross-fertilisation. He welcomed its support for his supposition that cross-fertilisation in flowering plants tended to allow their offspring to avoid possible disadvantages resulting from self-fertilisation, and by 1845 he had verified many of Sprengel's observations.
A favourite walk took the Darwin family to a spot above the quiet Cudham
Cudham
Cudham is a village in the London Borough of Bromley in London, UK. It is located south-southeast of Charing Cross and about northwest of Sevenoaks....
valley, teeming with orchids including Cephalanthera
Cephalanthera
Cephalanthera , abbreviated Ceph in horticultural trade, is a genus of mostly terrestrial orchids. Members of this genus have rhizomes rather than tubers. About 15 species are currently recognised, several of them common in Europe, for example the Sword-leaved Helleborine C. longifolia...
, Neottia, fly orchids
Fly Orchid
Ophrys insectifera, the Fly Orchid, is a species of orchid and the type species of the genus Ophrys. It is native to Europe and favors sites with alkaline soil. The name arises because it resembles a fly, being totally dependent on flies and bees for pollination...
and musk orchids
Musk Orchid
The musk orchid is a commonly occurring species of European orchid.-Status in Britain:Musk orchids have a localised distribution in Britain. Sites where it is found include Ham Hill in Wiltshire....
. They called this place "Orchis Bank", and the whole family became involved in Darwin's researches. Darwin observed orchids every summer, but in twenty years, only on two occasions (when he noticed butterflies "sucking O. pyramidalis
Pyramidal orchid
The Pyramidal Orchid, Anacamptis pyramidalis, is an herbaceous perennial plant belonging to the Genus Anacamptis of the family Orchidaceae...
and Gymnadenia
Gymnadenia
Gymnadenia is a genus in the orchid family containing 22 terrestrial species.They can be found in damp meadows, fens and marshes, and on chalk or limestone, often in alpine regions of Europe and Asia up to the Himalayas. The Fragrant Orchid has been introduced into the USA.These hardy terrestrial...
") did he see insects visiting flowers.
In 1854, Darwin began to work full-time on the origin of species. He examined orchids and counted how often one or both pollinia
Pollinium
Pollinium, or plural pollinia, is a coherent mass of pollen grains in a plant.They are the product of only one anther, but are transferred, during pollination, as a single unit. This is regularly seen in plants such as orchids and many species of milkweeds .Most orchids have waxy pollinia...
(pollen masses) had been removed from their flowers, indicating that they had been visited by insects. He experimented with insect pollination to investigate whether, by cross-fertilising field crops such as Fabaceae
Fabaceae
The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family of flowering plants. The group is the third largest land plant family, behind only the Orchidaceae and Asteraceae, with 730 genera and over 19,400 species...
, they would yield more vigorous offspring, and published letters about his inconclusive results in The Gardeners' Chronicle in 1857 and 1858. He next applied Sprengel's methods to empirical research
Empirical research
Empirical research is a way of gaining knowledge by means of direct and indirect observation or experience. Empirical evidence can be analyzed quantitatively or qualitatively...
on orchids. Despite delays caused by recurring illness
Charles Darwin's illness
For much of his adult life, Charles Darwin's health was repeatedly compromised by an uncommon combination of symptoms, leaving him severely debilitated for long periods of time...
, he made progress on writing his planned "Big Book" on evolution, but when Alfred Russel Wallace
Alfred Russel Wallace
Alfred Russel Wallace, OM, FRS was a British naturalist, explorer, geographer, anthropologist and biologist...
's letter prompted joint publication of both of their theories of natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
in 1858, Darwin quickly wrote On the Origin of Species as an abstract of his theory, published on 22 November 1859. In this book, he gave credence to Sprengel's ideas on the advantages of "intercrossing", and noted: "Many of our orchidaceous plants absolutely require the visits of moths to remove their pollen masses and thus to fertilise them". He introduced his new concept, the process of coevolution, describing the co–adaptation
Co-adaptation
In biology, co-adaptation, or coadaptation refers to the mutual adaptation of:* Species: see mutualism, symbiosis* organs: see the evolution of the eye.* Genes or gene complexes: see Linkage disequilibrium, epistasis...
of bumblebee
Bumblebee
A bumble bee is any member of the bee genus Bombus, in the family Apidae. There are over 250 known species, existing primarily in the Northern Hemisphere although they are common in New Zealand and in the Australian state of Tasmania.Bumble bees are social insects that are characterised by black...
s and red clover, and speculating "how a flower and a bee might slowly become, either simultaneously or one after the other, modified and adapted in the most perfect manner to each other, by the continued preservation of individuals presenting mutual and slightly favourable deviations of structure." This was a theme he developed in his orchid book.
Botany as recreation
By the spring of 1860 he had tired of the grind of writing, and needed something fresh and interesting to study. During a family visit to relatives at Hartfield
Hartfield
Hartfield is a civil parish in East Sussex, England. Settlements within the parish include the village of Hartfield, Colemans Hatch, Hammerwood and Holtye, all lying on the northern edge of Ashdown Forest.-Geography:...
, he was searching for orchids when he noticed a sundew. He collected it and tried to feed it insects, thus beginning a long-term study of insectivorous plants
Carnivorous plant
Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic...
. He investigated other botanical
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
questions raised by his ideas of natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
, including the advantages of sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
in primula
Primula
Primula is a genus of 400–500 species of low-growing herbs in the family Primulaceae. They include primrose, auricula, cowslip and oxlip. Many species are grown for their ornamental flowers...
s, and the adaptive mechanisms
Adaptation
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....
that ensure cross-pollination in orchids. As an enthusiastic practical scientist, such investigations gave him a strong sense of personal enjoyment. He relished pitting his wits against nature, and following lucky hunches
Serendipity
Serendipity means a "happy accident" or "pleasant surprise"; specifically, the accident of finding something good or useful without looking for it. The word has been voted as one of the ten English words hardest to translate in June 2004 by a British translation company. However, due to its...
. His theory was a way of looking at the world, enabling him to find creative solutions to problems that traditional approaches could not solve. He later wrote, "I am like a gambler, & love a wild experiment."
Around the end of April 1860, Darwin discussed insect pollination with his friend Joseph Dalton Hooker
Joseph Dalton Hooker
Sir Joseph Dalton Hooker OM, GCSI, CB, MD, FRS was one of the greatest British botanists and explorers of the 19th century. Hooker was a founder of geographical botany, and Charles Darwin's closest friend...
, and mentioned the bee orchid
Bee Orchid
The Bee Orchid is an herbaceous perennial plant belonging to the family Orchidaceae.-Etymology:The name "Ophrys" derives from the Greek word "ophrys", meaning "eyebrow", while the Latin name of the species "apifera" refers to the bee-shaped lip.-Description: The Bee Orchid grows to a height of ....
. Darwin corresponded with Hooker's assistant Daniel Oliver
Daniel Oliver
Daniel Oliver, FRS was a British botanist.He was Librarian of the Herbarium, Royal Botanic Gardens, Kew from 1860–1890 and Keeper there from 1864–1890, and Professor of Botany at University College, London from 1861–1888....
, the senior curator at Kew Gardens, who became a follower of Darwin's ideas. At the start of June, Darwin wrote to The Gardeners' Chronicle
The Gardeners' Chronicle
The Gardeners' Chronicle was a British horticulture periodical. It lasted as a title in its own right for nearly 150 years and is still extant as part of the magazine Horticulture Week....
asking for readers' observations on how bee or fly orchids
Ophrys
The genus Ophrys is a large group of orchids from the alliance Orchis in the subtribe Orchidinae. There are many natural hybrids. The type species is Ophrys insectifera L.1753...
were fertilised. His letter described the mechanisms for insect fertilisation he had discovered in common British orchids, and reported his experimental observations that pollen masses were removed from Orchis morio
Green-winged Orchid
The Green-winged Orchid or Green-veined Orchid is a flowering plant of the orchid family, Orchidaceae....
and Orchis mascula plants in the open, but left in their pouches in adjacent plants under a glass bell jar
Bell jar
A bell jar is a piece of laboratory equipment used for creating vacuums.http://www.belljar.net/about.htm It can be similar in shape to a bell, and can be manufactured out of a variety of materials . A bell jar is placed on a base which is vented to a hose fitting, which can be connected via a hose...
. He wrote to American botanist Asa Gray
Asa Gray
-References:*Asa Gray. Dictionary of American Biography. American Council of Learned Societies, 1928–1936.*Asa Gray. Encyclopedia of World Biography, 2nd ed. 17 Vols. Gale Research, 1998.*Asa Gray. Plant Sciences. 4 vols. Macmillan Reference USA, 2001....
that he had been "so struck with admiration at the contrivances, that I have sent notice to Gardeners Chronicle", and made similar enquiries of other experts.
Darwin became engrossed in meticulous microscopic examination, tracing the complicated mechanisms of flowers that attracted insects by their nectar so that the insects transported pollen to cross-pollinate other plants, and on 19 July he told Hooker, "I am intensely interested on subject, just as at a game of chess." In September, he "dissected with the greatest interest" and wrote, "The contrivances for insect fertilisation in Orchids are multiform & truly wonderful & beautiful." By October, he had "a large mass of notes with many new facts", but set them aside "convinced that I ought to work on Variation & not amuse myself with interludes".
Research and draft
Gentry
Gentry denotes "well-born and well-bred people" of high social class, especially in the past....
sent specimens from across the British Isles. Darwin also tramped around the countryside with tin cans and biscuit boxes, collecting specimens which his gardeners potted up for him. His family joined in, and neighbours contributed to the research. As he had only a cold greenhouse
Greenhouse
A greenhouse is a building in which plants are grown. These structures range in size from small sheds to very large buildings...
, a friend on the other side of the village who had a hot-house allowed him to use that, and offered the services of his gardener to look after the delicate specimens. Darwin's aim was to show how the complex structures and life cycles of the plants could be explained by natural selection rather than by the handiwork of God; he saw the huge variety of flowers as a collection of ad hoc
Ad hoc
Ad hoc is a Latin phrase meaning "for this". It generally signifies a solution designed for a specific problem or task, non-generalizable, and not intended to be able to be adapted to other purposes. Compare A priori....
evolutionary adaptations. In June he described his examination of bee orchids
Bee Orchid
The Bee Orchid is an herbaceous perennial plant belonging to the family Orchidaceae.-Etymology:The name "Ophrys" derives from the Greek word "ophrys", meaning "eyebrow", while the Latin name of the species "apifera" refers to the bee-shaped lip.-Description: The Bee Orchid grows to a height of ....
as a passion, and his findings on insect fertilisation of orchids as "beautiful facts".
There were several replies to Darwin's enquiry in The Gardeners' Chronicle
The Gardeners' Chronicle
The Gardeners' Chronicle was a British horticulture periodical. It lasted as a title in its own right for nearly 150 years and is still extant as part of the magazine Horticulture Week....
seeking evidence to support his idea that pollen masses attached themselves to a convenient place on an insect's back or head, usually its proboscis
Proboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...
, to transport the pollen to another flower. One envelope appeared to be empty when it arrived at Down House, but when he looked further before discarding it he found several insect mouthparts with pollen masses attached. To help their daughter Henrietta
Etty Darwin
Henrietta Emma "Etty" Darwin, was a daughter of Charles Darwin and his wife Emma Wedgwood.Etty was born in Down House, Downe in 1843. She was Darwin's third daughter and the eldest daughter to reach adulthood after the eldest Annie died aged 10, and second daughter Mary died before becoming a...
convalesce from illness, the Darwins arranged to spend two months in Torquay
Torquay
Torquay is a town in the unitary authority area of Torbay and ceremonial county of Devon, England. It lies south of Exeter along the A380 on the north of Torbay, north-east of Plymouth and adjoins the neighbouring town of Paignton on the west of the bay. Torquay’s population of 63,998 during the...
. Darwin wrote:
He sought advice on obtaining the exotic South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
n Catasetum
Catasetum
Catasetum, abbreviated as Ctsm in horticultural trade, is a genus of the Orchid family , subfamily Epidendroideae, tribe Cymbidieae, subtribe Catasetinae, with 166 species....
, to see it eject pollen masses, as "I am got intensely interested on subject & think I understand pretty well all the British species." They went to Torquay on 1 July, and Darwin began writing his Orchid paper. By 10 August, he feared his paper would run "to 100 M.S. folio pages!!! The beauty of the adaptations of parts seems to me unparalleled ... I marvel often as I think over the diversity & perfection of the contrivances."
Idealism
In philosophy, idealism is the family of views which assert that reality, or reality as we can know it, is fundamentally mental, mentally constructed, or otherwise immaterial. Epistemologically, idealism manifests as a skepticism about the possibility of knowing any mind-independent thing...
and in 1856 had asked if it was "to be supposed for a moment that the beauty of colour and outline ... are any good to the animals? ... Who has ever dreamed of finding an utilitarian purpose in the forms and colours of flowers ... ?" Darwin had, and in the orchids he tackled the most difficult case. His ideas would transform the way naturalists thought about coloration.
The completed Orchis paper came to 140 folio pages, and Darwin decided against presenting it at the Linnean Society of London
Linnean Society of London
The Linnean Society of London is the world's premier society for the study and dissemination of taxonomy and natural history. It publishes a zoological journal, as well as botanical and biological journals...
, thinking of publishing a pamphlet instead. He offered the draft to John Murray
John Murray (publisher)
John Murray is an English publisher, renowned for the authors it has published in its history, including Jane Austen, Sir Arthur Conan Doyle, Lord Byron, Charles Lyell, Johann Wolfgang von Goethe, Herman Melville, and Charles Darwin...
who agreed to publish it as a book. Although Darwin feared a lack of public interest, he hoped it would serve to "illustrate how Natural History may be worked under the belief of the modification of Species." In discussions with Asa Gray about natural theology
Natural theology
Natural theology is a branch of theology based on reason and ordinary experience. Thus it is distinguished from revealed theology which is based on scripture and religious experiences of various kinds; and also from transcendental theology, theology from a priori reasoning.Marcus Terentius Varro ...
, he wrote that "it really seems to me incredibly monstrous to look at an orchid as created as we now see it. Every part reveals modification on modification."
As a popular and acceptable activity, botany had been taken up by many middle class ladies, and Darwin included these botany enthusiasts in his correspondence. On the recommendation of John Lindley
John Lindley
John Lindley FRS was an English botanist, gardener and orchidologist.-Early years:Born in Catton, near Norwich, England, John Lindley was one of four children of George and Mary Lindley. George Lindley was a nurseryman and pomologist and ran a commercial nursery garden...
, Darwin wrote to Lady Dorothy Nevill
Lady Dorothy Nevill
Lady Dorothy Fanny Nevill , was an English writer, hostess, horticulturist and plant collector.She was one of five children of Horatio Walpole, 3rd Earl of Orford and Mary Fawkener, daughter of William Augustus Fawkener, sometime envoy extraordinary at St Petersburg and close friend of Empress...
, who responded generously by sending numerous exotic orchids, and requested a signed photograph of him to hang in her sitting room next to portraits of her other notable friends, including Hooker.
Linnean Society paper
The orchid book was delayed because of illness, but Darwin continued to "look at it as a hobby-horse, which has given me great pleasure to ride". He was particularly astounded by the long spurSpur (biology)
A spur in botany is a spike, usually part of a flower.In certain plants, part of a sepal or petal develops into an elongated hollow spike extending behind the flower, containing nectar which is sucked by long-tongued animals . Plants with such structures include Delphinium, Aquilegia, Piperia, and...
of the Angraecum sesquipedale
Angraecum sesquipedale
Angraecum sesquipedale is an epiphytic orchid in the genus Angraecum that is endemic to Madagascar. The orchid was first discovered by the French botanist Louis-Marie Aubert du Petit-Thouars in 1798, but was not described until 1822...
flowers, one of the orchids sent by the distinguished horticulturist James Bateman
James Bateman
James Bateman was a landowner and accomplished horticulturist. He developed Biddulph Grange after moving there around 1840, from nearby Knypersley Hall...
, and wrote to Hooker "Good Heavens what insect can suck it[?]"
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
n Catasetum
Catasetum
Catasetum, abbreviated as Ctsm in horticultural trade, is a genus of the Orchid family , subfamily Epidendroideae, tribe Cymbidieae, subtribe Catasetinae, with 166 species....
orchid Hooker had given to Darwin had shown its "truly marvellous" mechanism, by which it shot out a pollinium
Pollinium
Pollinium, or plural pollinia, is a coherent mass of pollen grains in a plant.They are the product of only one anther, but are transferred, during pollination, as a single unit. This is regularly seen in plants such as orchids and many species of milkweeds .Most orchids have waxy pollinia...
at any insect touching a part of the flower "with sticky gland always foremost". This plant had astonished botanists in 1836 when Robert Hermann Schomburgk
Robert Hermann Schomburgk
Sir Robert Hermann Schomburgk , was a German-born explorer for Great Britain who carried out geographical, ethnological and botanical studies in South America and the West Indies, and also fulfilled diplomatic missions for Great Britain in the Dominican Republic and Thailand.-Biography:Schomburgk...
stated that he had seen one plant growing three distinct flowers which usually grew separately and had wrongly been categorised as three distinct genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
, namely Catasetum tridentatum, Monachanthus viridis, and Myanthus barbatus. John Lindley
John Lindley
John Lindley FRS was an English botanist, gardener and orchidologist.-Early years:Born in Catton, near Norwich, England, John Lindley was one of four children of George and Mary Lindley. George Lindley was a nurseryman and pomologist and ran a commercial nursery garden...
had remarked that "such cases shake to the foundation all our ideas of the stability of genera and species." One of Darwin's correspondents told of delight at growing a beautiful specimen of Myanthus barbatus imported from Demerara
Demerara
Demerara was a region in South America in what is now Guyana that was colonised by the Dutch in 1611. The British invaded and captured the area in 1796...
, then dismay when the plant flowered the next year as a simple Catasetum.
In view of this interest, Darwin prepared a paper on Catasetum as an extract from his forthcoming book, which was read to the Linnean Society of London
Linnean Society of London
The Linnean Society of London is the world's premier society for the study and dissemination of taxonomy and natural history. It publishes a zoological journal, as well as botanical and biological journals...
on 3 April 1862. Darwin solved the puzzle by showing that the three flowers were the male, female, and hermaphrodite forms of a single species, but as they differed so much from each other, they had been classified as different genera.
Publication
Darwin sent the incomplete manuscript to his publisher John MurrayJohn Murray (publisher)
John Murray is an English publisher, renowned for the authors it has published in its history, including Jane Austen, Sir Arthur Conan Doyle, Lord Byron, Charles Lyell, Johann Wolfgang von Goethe, Herman Melville, and Charles Darwin...
on 9 February 1862, while he was still working on the last chapter. Although anxious that the book might not sell, he could "say with confidence that the M.S. contains many new & very curious facts & conclusions". When the book was printed, he sent out presentation copies to all the individuals and societies who had helped him with his investigations, and to eminent botanists in Britain and abroad for review.
On 15 May 1862 the book was published under the full title of On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. In August, Darwin was "well contented with the sale of 768 copies; I shd. hope & expect that the remainder will ultimately be sold", but the book sold slowly and less than 2,000 copies of the first edition were printed. An expanded edition translated into French was published in Paris in 1870, and in 1877 Murray brought out a revised and expanded second edition, with the shortened title The various contrivances by which orchids are fertilised by insects. This was also published by D. Appleton & Company
D. Appleton & Company
D. Appleton & Company was an American company founded by Daniel Appleton , who opened a general store which included books.- Timeline :* 1813 Relocated from Haverhill to Boston and imported books from England...
of New York in 1877, and a German translation was published in the same year. Despite being well praised by botanists, only about 6,000 copies of the English editions had been sold by 1900.
Content
Darwin set out a detailed study of common descent with modificationsCommon descent
In evolutionary biology, a group of organisms share common descent if they have a common ancestor. There is strong quantitative support for the theory that all living organisms on Earth are descended from a common ancestor....
by expanding on the theme of coevolution between local populations of insects and flowering plants that he had briefly discussed in On the Origin of Species. He examined numerous ways in which orchids vary, showing how they had diverged and developed specialised pollen-dispersal mechanisms. The intricate morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
and anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
of each flower was carefully described. Apparently trivial details were examined in relation to natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
to demonstrate how slight variations in similar structures
Homology (biology)
Homology forms the basis of organization for comparative biology. In 1843, Richard Owen defined homology as "the same organ in different animals under every variety of form and function". Organs as different as a bat's wing, a seal's flipper, a cat's paw and a human hand have a common underlying...
of closely related flowers led to specialised modifications that provided various pollinators (insects) with different ways to cross-fertilise. The mass of descriptive detail was a great achievement, but the result is demanding to read.
In the introduction, Darwin explained his aim of meeting complaints that detailed support for his theory was lacking in On the Origin of Species. He chose orchids for his subject as "amongst the most singular and most modified forms in the vegetable kingdom" in the hope of inspiring work on other species, and felt that "the study of organic beings may be as interesting to an observer who is fully convinced that the structure of each is due to secondary laws, as to one who views every trifling detail of structure as the result of the direct interposition of the Creator." He gave due credit to previous authors who had described the agency of insects in fertilising orchids, and all who had helped him.
British orchids
The first mechanism described is that of Orchis mascula, which serves as an introduction to the explanation of other Orchidaceae
Orchidaceae
The Orchidaceae, commonly referred to as the orchid family, is a morphologically diverse and widespread family of monocots in the order Asparagales. Along with the Asteraceae, it is one of the two largest families of flowering plants, with between 21,950 and 26,049 currently accepted species,...
. In the upper part of the flower a petal shelters the male organ
Stamen
The stamen is the pollen producing reproductive organ of a flower...
which has two packages of pollen grains, held together by thin elastic threads. These pollen masses
Pollinium
Pollinium, or plural pollinia, is a coherent mass of pollen grains in a plant.They are the product of only one anther, but are transferred, during pollination, as a single unit. This is regularly seen in plants such as orchids and many species of milkweeds .Most orchids have waxy pollinia...
stand side by side and have stalks down to adhesive balls in a cup which keeps them moist and sticky. When an insect lands on the large projecting lower petal, the labellum
Labellum
Labellum is the Latin diminutive of labium, meaning lip. These are anatomical terms used descriptively in biology, for example in Entomology and botany.-Botany:...
, and pushes its head and proboscis
Proboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...
into the centre of the flower and down to the nectary, it breaks the cup and the adhesive balls attach the pollen masses to the front of the insect. As the insect flies off, each stalk rotates the pollen mass downwards and forwards so that when the insect lands on another flower the pollen masses attached to the insect pass under the male organ and leave pollen on the female organ
Gynoecium
Gynoecium is most commonly used as a collective term for all carpels in a flower. A carpel is the ovule and seed producing reproductive organ in flowering plants. Carpels are derived from ovule-bearing leaves which evolved to form a closed structure containing the ovules...
, achieving cross fertilisation. Darwin envisaged:
This is followed by descriptions of the differences in the mechanisms of several other orchids. In Orchis pyramidalis
Pyramidal orchid
The Pyramidal Orchid, Anacamptis pyramidalis, is an herbaceous perennial plant belonging to the Genus Anacamptis of the family Orchidaceae...
, the adhesive balls are combined together into a strap or saddle shape, which curls round the thin proboscis
Proboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...
of a moth or butterfly to attach to it the pair of pollen masses, illustrated in the book by figure 4 showing a moth's head with seven pairs of pollen masses attached to its proboscis.
Bee Orchid
The Bee Orchid is an herbaceous perennial plant belonging to the family Orchidaceae.-Etymology:The name "Ophrys" derives from the Greek word "ophrys", meaning "eyebrow", while the Latin name of the species "apifera" refers to the bee-shaped lip.-Description: The Bee Orchid grows to a height of ....
showed adaptation
Adaptation
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....
for self-fertilisation, its mechanism also enabled occasional cross-fertilisation, creating the biological diversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
that Darwin felt was needed for vigorous survival, which could not be provided by self-fertilisation. As an example of "how beautifully everything is contrived", Darwin described how he had found that in Spiranthes
Spiranthes
Spiranthes, commonly called Ladies'-tresses, is a genus of orchids Spiranthes, commonly called Ladies'-tresses, is a genus of orchids Spiranthes, commonly called Ladies'-tresses, is a genus of orchids (family (Orchidaceae) belonging to the subfamily Orchidoideae.It has a very wide, almost...
flowers the pollen is ready for collection before access is open for the female organ to receive pollen. At Torquay
Torquay
Torquay is a town in the unitary authority area of Torbay and ceremonial county of Devon, England. It lies south of Exeter along the A380 on the north of Torbay, north-east of Plymouth and adjoins the neighbouring town of Paignton on the west of the bay. Torquay’s population of 63,998 during the...
he had watched bees visiting spires of these flowers, starting at the bottom of the spire and working their way up to the topmost flowers. He speculated that if bees moved from top to top of the spires, the pollen clusters they collected from the most recently opened flowers would be wasted as the topmost flowers on the next spike would not be ready to receive pollen. A bee starting at the lowest flowers on the first spire it visited would continue up until it reached flowers that still had their pollen masses to attach to the bee, then would fly to the mature lower flowers on another plant, and fertilise them. By this co-ordinated process, the bee would add "to her store of honey" while perpetuating the flowers "which will yield honey to future generations of bees".
Exotic orchids
Angraecum sesquipedale
Angraecum sesquipedale is an epiphytic orchid in the genus Angraecum that is endemic to Madagascar. The orchid was first discovered by the French botanist Louis-Marie Aubert du Petit-Thouars in 1798, but was not described until 1822...
flowers implied the need for an as yet unknown moth with a proboscis
Proboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...
10–11 inches (250–275 mm) long to pollinate these flowers in Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
. He viewed this as the outcome of a coevolutionary race, writing that "there has been a race in gaining length between the nectary of the Angræcum and the proboscis of certain moths". This wastefulness is familiar in modern terms as the idea of an evolutionary arms race
Evolutionary arms race
In evolutionary biology, an evolutionary arms race is an evolutionary struggle between competing sets of co-evolving genes that develop adaptations and counter-adaptations against each other, resembling an arms race, which are also examples of positive feedback...
, but was disturbing to biologists of the time who believed that adaptations were the outcome of benevolent divine purpose
Teleological argument
A teleological or design argument is an a posteriori argument for the existence of God based on apparent design and purpose in the universe. The argument is based on an interpretation of teleology wherein purpose and intelligent design appear to exist in nature beyond the scope of any such human...
.
Darwin described "the most remarkable of all Orchids", Catasetum
Catasetum
Catasetum, abbreviated as Ctsm in horticultural trade, is a genus of the Orchid family , subfamily Epidendroideae, tribe Cymbidieae, subtribe Catasetinae, with 166 species....
, and showed how in these flowers, "as throughout nature, pre-existing structures and capacities [had been] utilised for new purposes". He explained the mechanism in which the pollen masses of the pollinium
Pollinium
Pollinium, or plural pollinia, is a coherent mass of pollen grains in a plant.They are the product of only one anther, but are transferred, during pollination, as a single unit. This is regularly seen in plants such as orchids and many species of milkweeds .Most orchids have waxy pollinia...
were connected by a bent stalk or pedicel
Pedicel (botany)
A pedicel is a stem that attaches single flowers to the main stem of the inflorescence. It is the branches or stalks that hold each flower in an inflorescence that contains more than one flower....
to a sticky disc kept moist at the back of the flower. When an insect touched an "antenna" projecting from the back of the flower, this released the bent pedicel which sprang straight and fired the pollinium, sticky disc first, at the insect. In experiments, Darwin had imitated this action using a whalebone spring. He vividly illustrated how the flower ejected the pollinium with considerable force: "I touched the antennæ of C. callosum whilst holding the flower at about a yard's distance from the window, and the pollinium hit the pane of glass, and adhered to the smooth vertical surface by its adhesive disc."
Final chapter
Darwin noted that the essential nectar, secretedSecretion
Secretion is the process of elaborating, releasing, and oozing chemicals, or a secreted chemical substance from a cell or gland. In contrast to excretion, the substance may have a certain function, rather than being a waste product...
to attract insects, seemed also in some cases to act as an excretion
Excretion
Excretion is the process by which waste products of metabolism and other non-useful materials are eliminated from an organism. This is primarily carried out by the lungs, kidneys and skin. This is in contrast with secretion, where the substance may have specific tasks after leaving the cell...
: "It is in perfect accordance with the scheme of nature, as worked out by natural selection, that matter excreted to free the system from superfluous or injuring substances should be utilised for purposes of the highest importance." Homologies
Homology (biology)
Homology forms the basis of organization for comparative biology. In 1843, Richard Owen defined homology as "the same organ in different animals under every variety of form and function". Organs as different as a bat's wing, a seal's flipper, a cat's paw and a human hand have a common underlying...
of the orchid flowers of orchids showed them all to be based on "fifteen groups of vessels, arranged three within three, in alternating order". He disparaged the idea that this was an "ideal type" fixed by the Omnipotent Creator, but attributed it instead to its "descent from some monocotyledon
Monocotyledon
Monocotyledons, also known as monocots, are one of two major groups of flowering plants that are traditionally recognized, the other being dicotyledons, or dicots. Monocot seedlings typically have one cotyledon , in contrast to the two cotyledons typical of dicots...
ous plant, which, like so many other plants of the same division, possessed fifteen organs, arranged alternately three within three in five whorls; and that the now wonderfully changed structure of the flower is due to a long course of slow modification,—each modification having been preserved which was useful to each plant, during the incessant changes to which the organic and the inorganic world has been exposed".
Describing the final end state of the whole flower cycle as the production of seed, he set out a simple experiment in which he took a ripe seed capsule and arranged the seeds in a line, then counted the seeds in one-tenth of an inch (2.5 mm). By multiplication he found that each plant produced enough seeds to plant 1 acres (4,046.9 m²) of ground, and the great grandchildren of a single plant could "carpet the entire surface of the land throughout the globe" if unchecked.
In conclusion, he felt that the book had "shown that Orchids exhibit an almost endless diversity of beautiful adaptations. When this or that part has been spoken of as contrived for some special purpose, it must not be supposed that it was originally always formed for this sole purpose. The regular course of events seems to be, that a part which originally served for one purpose, by slow changes becomes adapted for widely different purposes."
He was almost exasperated by the inventiveness of forms in nature; "In my examination of Orchids, hardly any fact has so much struck me as the endless diversity of structure,—the prodigality of resources,—for gaining the very same end, namely, the fertilisation of one flower by the pollen of another." His focus on detail was justified, as "The use of each trifling detail of structure is far from a barren search to those who believe in natural selection." The "contrivances and beautiful adaptations" slowly acquired through slight variations, subjected to natural selection "under the complex and ever-varying conditions of life", far transcended the most fertile imagination. The mechanisms to transport the pollen of one flower or of one plant to another flower or plant underlined the importance of cross-fertilisation: "For may we not further infer as probable, in accordance with the belief of the vast majority of the breeders of our domestic productions, that marriage between near relatives is likewise in some way injurious,—that some unknown great good is derived from the union of individuals which have been kept distinct for many generations?"
Reception
Daniel Oliver
Daniel Oliver, FRS was a British botanist.He was Librarian of the Herbarium, Royal Botanic Gardens, Kew from 1860–1890 and Keeper there from 1864–1890, and Professor of Botany at University College, London from 1861–1888....
thought it "very extraordinary", and even Darwin's old beetle-hunting rival Charles Babington
Cardale Babington
Charles Cardale Babington was an English botanist and archaeologist. He was elected a Fellow of the Royal Society in 1851....
, by then professor of botany at the University of Cambridge
University of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...
and inclined to oppose natural selection, called it "exceedingly interesting and valuable ... highly satisfactory in all respects. The results are most curious and the skill shown in discovering them equally so." George Bentham
George Bentham
George Bentham CMG FRS was an English botanist, characterized by Duane Isely as "the premier systematic botanist of the nineteenth century".- Formative years :...
praised its value in opening "a new field for observing the wonderful provisions of Nature ... a new and unexpected track to guide us in the explanation of phenomena which had before that appeared so irreconcilable with the ordinary prevision and method shown in the organised world."
The book's success in botanical circles was enhanced following Bentham's public endorsement. In his presidential address to the Linnean Society
Linnean Society of London
The Linnean Society of London is the world's premier society for the study and dissemination of taxonomy and natural history. It publishes a zoological journal, as well as botanical and biological journals...
on 24 May 1862, Bentham praised the book as exemplifying the biological method, and said that it had nearly overcome his opposition to the Origin. In his address in 1863 he stated that "Mr Darwin has shown how changes may take place", and described it as "an unimpeachable example of a legitimate hypothesis" in compliance with John Stuart Mill
John Stuart Mill
John Stuart Mill was a British philosopher, economist and civil servant. An influential contributor to social theory, political theory, and political economy, his conception of liberty justified the freedom of the individual in opposition to unlimited state control. He was a proponent of...
's scientific method
Scientific method
Scientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering empirical and measurable evidence subject to specific principles of...
. This endorsement favourably influenced Miles Joseph Berkeley
Miles Joseph Berkeley
Miles Joseph Berkeley was an English cryptogamist and clergyman, and one of the founders of the science of plant pathology....
, Charles Victor Naudin
Charles Victor Naudin
Charles Victor Naudin was a French naturalist and botanist.-Biography:He studied at Bailleul-sur-Thérain in 1825, then to Limoux, a graduate of the University of Montpellier in 1837, he was preceptor in 1838 and obtained his doctorate in 1842...
, Alphonse Pyramus de Candolle, Jean Louis Quatrefages
Jean Louis Armand de Quatrefages de Bréau
Jean Louis Armand de Quatrefages de Bréau was a French naturalist.- Life :He was born at Berthézène, in the commune of Valleraugue , the son of a Protestant farmer. He studied medicine at Strasbourg, where he took the double degree of M.D...
, and Charles Daubeny
Charles Daubeny
Charles Giles Bridle Daubeny was an English chemist, botanist and geologist.Daubeny was born at Stratton near Cirencester in Gloucestershire, the son of the Rev. James Daubeny. He studied at Magdalen College, Oxford under Dr. John Kidd...
.
In June 1862, Darwin welcomed favourable reviews in the press and wrote to Hooker; "Well my orchis-book is a success (but I do not know whether it sells) after cursing my folly in writing it". He told his publisher, "The Botanists praise my Orchid-book to the skies", and to Asa Gray
Asa Gray
-References:*Asa Gray. Dictionary of American Biography. American Council of Learned Societies, 1928–1936.*Asa Gray. Encyclopedia of World Biography, 2nd ed. 17 Vols. Gale Research, 1998.*Asa Gray. Plant Sciences. 4 vols. Macmillan Reference USA, 2001....
he said, "I am fairly astonished at the success of my book with botanists." Darwin's geologist friend Charles Lyell
Charles Lyell
Sir Charles Lyell, 1st Baronet, Kt FRS was a British lawyer and the foremost geologist of his day. He is best known as the author of Principles of Geology, which popularised James Hutton's concepts of uniformitarianism – the idea that the earth was shaped by slow-moving forces still in operation...
gave it enthusiastic praise: "next to the Origin, as the most valuable of all Darwin's works." However, the book attracted little attention from the general public, and in September Darwin told his cousin Fox
William Darwin Fox
The Reverend William Darwin Fox was an English clergyman, naturalist, and a 2nd cousin of Charles Robert Darwin.- Early life :...
, "Hardly any one not a botanist, except yourself, as far as I know, has cared for it." The book baffled a general public more interested in controversy over gorillas and cavemen. There were some reviews in gardening magazines, but few natural philosophers or zoologists noticed the book, and hardly any learned appraisals appeared.
Theological responses
Natural theology
Natural theology is a branch of theology based on reason and ordinary experience. Thus it is distinguished from revealed theology which is based on scripture and religious experiences of various kinds; and also from transcendental theology, theology from a priori reasoning.Marcus Terentius Varro ...
and its teleological
Teleological argument
A teleological or design argument is an a posteriori argument for the existence of God based on apparent design and purpose in the universe. The argument is based on an interpretation of teleology wherein purpose and intelligent design appear to exist in nature beyond the scope of any such human...
approach to design in nature, the Saturday Review
Saturday Review (London)
The Saturday Review of politics, literature, science, and art was a London weekly newspaper established by A. J. B. Beresford Hope in 1855....
thought that it would avoid the angry polemics aroused by On the Origin of Species. The Literary Churchman welcomed "Mr. Darwin's expression of admiration at the contrivances in orchids", only complaining that it was too indirect a way of saying "O Lord, how manifold are Thy works!" (Psalm
Psalms
The Book of Psalms , commonly referred to simply as Psalms, is a book of the Hebrew Bible and the Christian Bible...
104:24
Psalm 104
Psalm 104 is a poem from the Book of Psalms in the Hebrew Bible, describing the ongoing act of God continuously bringing the world into existence. German philosopher Johann Gottfried Herder remarked, "It is worth studying the Hebrew language for ten years in order to read Psalm 104 in the original"...
) Darwin regarded these theological views as irritating misunderstandings, but wrote to Asa Gray
Asa Gray
-References:*Asa Gray. Dictionary of American Biography. American Council of Learned Societies, 1928–1936.*Asa Gray. Encyclopedia of World Biography, 2nd ed. 17 Vols. Gale Research, 1998.*Asa Gray. Plant Sciences. 4 vols. Macmillan Reference USA, 2001....
describing his approach as a "flank movement on the enemy". By showing that the "wonderful contrivances" of the orchid have discoverable evolutionary histories, Darwin was countering claims by natural theologians that the organisms were examples of the perfect work of the Creator.
There was considerable controversy surrounding Darwin's prediction that a moth would be found in Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
with a long proboscis matching the nectary of Angraecum sesquipedale
Angraecum sesquipedale
Angraecum sesquipedale is an epiphytic orchid in the genus Angraecum that is endemic to Madagascar. The orchid was first discovered by the French botanist Louis-Marie Aubert du Petit-Thouars in 1798, but was not described until 1822...
. An anonymous article in the Edinburgh Review
Edinburgh Review
The Edinburgh Review, founded in 1802, was one of the most influential British magazines of the 19th century. It ceased publication in 1929. The magazine took its Latin motto judex damnatur ubi nocens absolvitur from Publilius Syrus.In 1984, the Scottish cultural magazine New Edinburgh Review,...
of October 1862 by George Campbell, 8th Duke of Argyll
George Campbell, 8th Duke of Argyll
George John Douglas Campbell, 8th Duke of Argyll KG, KT, PC, FRS, FRSE , styled Marquess of Lorne until 1847, was a Scottish peer, Liberal politician as well as a writer on science, religion, and the politics of the 19th century.-Background:Argyll was born at Ardencaple Castle, Dunbartonshire, the...
, argued that Darwin's wording implied purpose, and concluded that "We know, too, that these purposes and ideas are not our own, but the ideas and purposes of Another." He considered Darwin's explanations the "most unsatisfactory conjectures", and raised obscure metaphysical objections while supporting a kind of creative evolutionism. Emma Darwin thought that although Argyll was "quite opposed" to Darwin's views, "he praises the Orchids in such an enthusiastic way that he will do it a good turn". Darwin was delighted to find that a well written article "smashing" Argyll's review was by one of Darwin's own nephews.
Argyll went on in his 1867 book The Reign of Law to cleverly ridicule Darwin's ideas, particularly the prediction of a moth in Madagascar with a proboscis 10–11 inches (250–275 mm) long. He believed that adaptations showed divine purpose, not a mindless evolutionary arms race
Evolutionary arms race
In evolutionary biology, an evolutionary arms race is an evolutionary struggle between competing sets of co-evolving genes that develop adaptations and counter-adaptations against each other, resembling an arms race, which are also examples of positive feedback...
. In his response Creation by Law later that year, Alfred Russel Wallace
Alfred Russel Wallace
Alfred Russel Wallace, OM, FRS was a British naturalist, explorer, geographer, anthropologist and biologist...
produced a detailed explanation of how the nectary could have evolved through natural selection, and stated that he had carefully measured moths in the British Museum
British Museum
The British Museum is a museum of human history and culture in London. Its collections, which number more than seven million objects, are amongst the largest and most comprehensive in the world and originate from all continents, illustrating and documenting the story of human culture from its...
, finding that the proboscis of Macrosila cluentius
Neococytius cluentius
The Cluentius Sphinx is a moth of the Sphingidae family. It is found in northern South America, Central America, Mexico and the Caribbean. It is rare on Cuba. It has been recorded from North America, from Mississippi north to Michigan and Illinois.The wingspan is 140-160 mm...
from South America was 9 inches (235 mm) long, and the proboscis of Macrosila morganii from tropical Africa (since renamed Xanthopan morgani
Xanthopan morgani
Xanthopan morgani, or Morgan's Sphinx, is a very large hawk moth from West Africa and Madagascar. It is the sole member of its genus, and little is known of the biology, though the adults have been found to visit orchids .In January 1862 while researching insect pollination of orchids, Charles...
) was 7 inches (190 mm) long. An enquiry raised in 1873 was answered by Darwin's friend Hermann Müller
Hermann Müller (botanist)
Heinrich Ludwig Hermann Müller , German botanist who provided important evidence for Darwin's theory of evolution. He was the author in 1873 of Die Befruchtung der Blumen durch Insekten, a book translated at the suggestion of Darwin in 1883 as The fertilisation of flowers...
, who stated that his brother Fritz Müller
Fritz Müller
Johann Friedrich Theodor Müller , better known as Fritz Müller, and also as Müller-Desterro, was a German biologist and physician who emigrated to southern Brazil, where he lived in and near the German community of Blumenau, Santa Catarina...
had caught a sphinx moth in Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
with a proboscis nearly 10 inches (254 mm) long. Darwin's anticipation was fully met in 1903, when a subspecies of Xanthopan morgani was found in Madagascar with a proboscis about 12 inches (300 mm) long, and was named Xanthopan morgani praedicta to celebrate this verification of a testable prediction made by Darwin on the basis of his theory of natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
.
Influence
Michael GhiselinMichael Ghiselin
Michael T. Ghiselin is an American biologist, philosopher/historian of biology currently at the California Academy of Sciences.B.A., University of Utah ; Ph.D., Stanford University ; Postdoctoral Fellow, Harvard University ; Postdoctoral Fellow, Marine Biological Laboratory ; Assistant Professor of...
has expressed the view that all studies of coevolution follow directly or indirectly from Darwin's orchid book, which was also the origin of all work on the evolution of extreme specialisation. Its publication led almost immediately to research by many other naturalists into specialisation and coevolution, in some cases analysing other taxa
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
. In his autobiography
The Autobiography of Charles Darwin
The Autobiography of Charles Darwin is the autobiography of the British naturalist Charles Darwin which was published in 1887, five years after his death....
, Darwin modestly recalled how this work had revived interest in Christian Konrad Sprengel
Christian Konrad Sprengel
Christian Konrad Sprengel was a German theologist, teacher and, most importantly, a naturalist. He is most famously known for his research into plant sexuality....
's neglected ideas:
Among the many prominent biologists who began research on coevolution, Hermann Müller
Hermann Müller (botanist)
Heinrich Ludwig Hermann Müller , German botanist who provided important evidence for Darwin's theory of evolution. He was the author in 1873 of Die Befruchtung der Blumen durch Insekten, a book translated at the suggestion of Darwin in 1883 as The fertilisation of flowers...
was particularly interested in the evolutionary sequence in which insects and flowers became adapted to each other. Like Darwin, he began with the premise that flowers were adapted to ensure cross-fertilisation, and added his own premise that most insects were not "limited by hereditary instinct to particular flowers". On this basis, he developed the view that specialisation develops from the need for flowers to attract pollinating insects (without making access too easy for non-pollinators), and from the evolution of pollinators to adapt to changes in the location of rewards such as nectar. He found that Alpine flowers
Alpine plant
Alpine plants are plants that grow in the alpine climate, which occurs at high elevation and above the tree line. Alpine plants grow together as a plant community in alpine tundra.-Alpine plant diversity:...
tended to be visited by bees at lower altitudes, and by butterflies at higher altitudes, beginning research on the idea that plants at different altitudes were specialised for different pollinators. By comparing related plant species that he thought had diverged in form from a common ancestor, and testing whether they were visited by butterflies or bees, he was the first to use a combination of morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
and ecological
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
approaches to understand patterns in the evolution of interactions and specialisation. His brother Fritz Müller
Fritz Müller
Johann Friedrich Theodor Müller , better known as Fritz Müller, and also as Müller-Desterro, was a German biologist and physician who emigrated to southern Brazil, where he lived in and near the German community of Blumenau, Santa Catarina...
used similar methods when studying mimicry in Brazil. The early development of ideas on specialisation and coevolution became increasingly focused on the problem of mimicry; Henry Walter Bates
Henry Walter Bates
Henry Walter Bates FRS FLS FGS was an English naturalist and explorer who gave the first scientific account of mimicry in animals. He was most famous for his expedition to the Amazon with Alfred Russel Wallace in 1848. Wallace returned in 1852, but lost his collection in a shipwreck...
had initially raised this issue in a paper read to the Linnean Society of London
Linnean Society of London
The Linnean Society of London is the world's premier society for the study and dissemination of taxonomy and natural history. It publishes a zoological journal, as well as botanical and biological journals...
in December 1861 in Darwin's presence, and published in November 1862.
Others basing their studies of reproductive ecology on Darwin's evolutionary approach included Friedrich Hildebrand and Severin Axell in Europe, Asa Gray
Asa Gray
-References:*Asa Gray. Dictionary of American Biography. American Council of Learned Societies, 1928–1936.*Asa Gray. Encyclopedia of World Biography, 2nd ed. 17 Vols. Gale Research, 1998.*Asa Gray. Plant Sciences. 4 vols. Macmillan Reference USA, 2001....
and Charles Robertson in North America. In Italy, Federigo Delpino adopted the theory of descent but like Sprengel had a teleological
Teleology
A teleology is any philosophical account which holds that final causes exist in nature, meaning that design and purpose analogous to that found in human actions are inherent also in the rest of nature. The word comes from the Greek τέλος, telos; root: τελε-, "end, purpose...
approach and explained the mechanisms of flowers by the intervention of a "psychovitalistic intelligence". Delpino classified flowers on the basis of the pollinators they attracted, and coined many of the terms still in use such as pollination syndrome
Pollination syndrome
Pollination syndromes are suites of flower traits that have evolved in response to natural selection imposed by different pollen vectors, which can be abiotic or biotic, such as birds, bees, flies, and so forth. These traits include flower shape, size, colour, odour, reward type and amount, nectar...
and ornithophily
Ornithophily
Ornithophily or Bird Pollination is the pollination of flowering plants by birds. This coevolutionary association is derived from insect pollination and is particularly well developed in some parts of the world, especially in the tropics and on some island chains. The association involves several...
. There was an enormous increase in knowledge during this period. In 1874, Asa Gray paid tribute to Darwin's work on orchids for explaining "all these and other extraordinary structures, as well as of the arrangement of blossoms in general, and even the very meaning and need of sexual propagation". He credited Darwin with establishing the understanding that "Nature abhors close fertilization".
By the end of the 19th century, there were so many uncritical and unproven speculations about floral mechanisms that floral ecology became discredited. In the 1920s, it was revived with further developments in detailed analyses of insects' senses, led by researchers Frederic Clements
Frederic Clements
Frederic Edward Clements was an American plant ecologist and pioneer in the study of vegetation succession.-Biography:...
, Karl von Frisch
Karl von Frisch
Karl Ritter von Frisch was an Austrian ethologist who received the Nobel Prize in Physiology or Medicine in 1973, along with Nikolaas Tinbergen and Konrad Lorenz....
and others. Their experiments resulted in new information, including the discovery that some insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s have ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
vision, and findings involving bee learning and communication
Bee learning and communication
Honey bees learn and communicate in order to find food sources and for other means.-Learning:Learning is essential for efficient foraging. Honey bees are unlikely to make many repeat visits if a plant provides little in the way of reward...
. Modern floral ecology has been reinvigorated by its relevance for evolutionary studies.
Further research by Darwin
Greenhouse
A greenhouse is a building in which plants are grown. These structures range in size from small sheds to very large buildings...
. The gardener drew up plans, and Darwin investigated stoves and ventilation devices. When it was completed in February 1863 he asked Hooker for some plants from Kew Gardens, writing "I long to stock it, just like a school-boy", and sent his butler with a cart. When over 160 different plants were delivered, Darwin made apologetic remarks about depleting the national collection. He told Hooker "You cannot imagine what pleasure your plants give me ... Henrietta & I go & gloat over them." Darwin's life was changed by having a warm hothouse to spend time in before his walk round the Sandwalk, and in the 1870s he had several more hothouses built. The children later remembered this routine and the gardeners attending to Darwin's experimental plants, as well as the way that Darwin used simple equipment for his experiments, dissecting and measuring plants and seeds.
A chance observation "thoroughly aroused" Darwin's attention to a surprising decrease in vigour of the offspring of Linaria vulgaris
Linaria vulgaris
Linaria vulgaris is a species of toadflax , native to most of Europe and northern Asia, from the United Kingdom south to Spain in the west, and east to eastern Siberia and western China...
following only one instance of self-fertilisation, and after eleven years of experimental work he published The Effects of Cross and Self Fertilisation in the Vegetable Kingdom
The Effects of Cross and Self Fertilisation in the Vegetable Kingdom
The Effects of Cross and Self Fertilisation in the Vegetable Kingdom is a book on evolution in plants by Charles Darwin, first published in 1876. In this book Darwin examines the effects of cross and self fertilisation of plants and provides experimental evidence for a hypothesis stated in his...
in 1876 as "a complement to the 'Fertilisation of Orchids,' because it shows how important are the results of cross-fertilisation which are ensured by the mechanisms described in that book." He told a friend "I cannot endure doing nothing", and resumed his work on orchids, assisted in his research by his son Francis Darwin
Francis Darwin
Sir Francis "Frank" Darwin, FRS , a son of the British naturalist and scientist Charles Darwin, followed his father into botany.-Biography:Francis Darwin was born in Down House, Downe, Kent in 1848...
. He corresponded about orchids with Fritz Müller
Fritz Müller
Johann Friedrich Theodor Müller , better known as Fritz Müller, and also as Müller-Desterro, was a German biologist and physician who emigrated to southern Brazil, where he lived in and near the German community of Blumenau, Santa Catarina...
, and almost completely rewrote the book with a considerable amount of new material, much of which was contributed by Müller. The revised edition was published in 1877.
Francis Darwin described it as characteristic that his father delighted in the observations that preceded the publication of Fertilisation of Orchids, not the applause which followed it. He quoted one of his father's last letters about orchids, written in 1880:
Commemoration of Darwin's work on orchids
Kent Wildlife TrustKent Wildlife Trust
Kent Wildlife Trust covers the county of Kent, England, and is one of the largest of the 47 Wildlife Trust organisations in the United Kingdom, the Isle of Man and Alderney...
manages Downe Bank
Downe Bank
Downe Bank is a nature reserve owned and managed by the Kent Wildlife Trust in the North Downs, close to Downe in the London Borough of Bromley. It is a Site of Special Scientific Interest together with the neighbouring High Elms Country Park...
, which is near Down House and was a favourite place of the Darwin family, who called it 'Orchis Bank' because of the many wild orchids which grew there. It is now part of the 'Downe Bank and High Elms
High Elms Country Park
High Elms Country Park is an extensive public park on the North Downs in Farnborough in the London Borough of Bromley. It is a Local Nature Reserve, and together with the neighbouring Downe Bank, a Site of Special Scientific Interest. The park surrounds High Elms Golf Course, and has extensive...
' Site of Special Scientific Interest
Site of Special Scientific Interest
A Site of Special Scientific Interest is a conservation designation denoting a protected area in the United Kingdom. SSSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in Great Britain are based upon...
. Darwin’s observations of local orchids and their insect pollinators gave him the evidence for co-evolution which provided the basis for the Fertilisation of Orchids." Experts have identified "Orchis Bank" as the species-rich setting encapsulated in the closing paragraph of On the Origin of Species, in which Darwin wrote:
Darwin's home and its surroundings, including specifically "Orchis Bank", have been called his landscape laboratory, and together were nominated in January 2009 for designation as a World Heritage Site
World Heritage Site
A UNESCO World Heritage Site is a place that is listed by the UNESCO as of special cultural or physical significance...
. The bid was made by a partnership led by the London Borough of Bromley
London Borough of Bromley
The London Borough of Bromley is a London borough of south east London, England and forms part of Outer London. The principal town in the borough is Bromley.-Geography:...
, which now includes Downe
Downe
Downe is a village in the London Borough of Bromley in London, UK.Downe is south west of Orpington and south east of Charing Cross. Downe lies in a wooded valley, and much of the centre of the village is unchanged; the former village school now acts as the village hall.-Darwin:Charles Darwin...
. It was included in the 39 proposed properties, but was not in the 21 new sites selected for the list.
The influence of Darwin's work was commemorated in the Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...
's 15th Annual Orchid Show, Orchids Through Darwins Eyes, 24 January to 26 April 2009.
External links
- The Complete Works of Charles Darwin OnlineThe Complete Works of Charles Darwin OnlineThe Complete Work of Charles Darwin Online is a freely-accessible website containing the complete print and manuscript works of Charles Darwin, as well as related supplementary material.- Overview :...
gives online access to Darwin's writings: see for links to English, French and German editions of the book. - The Darwin Correspondence Project is the source used for letters, published online following their publication in print as explained in Darwin Correspondence Project » The Correspondence of Charles Darwin. See also Correspondence of Charles DarwinCorrespondence of Charles DarwinThe British naturalist Charles Darwin had correspondence with numerous other luminaries of his age and members of his family. These have provided many insights about the nineteenth century, from scientific exploration and travel to religious debate and discussion...
.