Drosera falconeri
Encyclopedia
Drosera falconeri is a carnivorous plant
in the genus Drosera. It is endemic to the Northern Territory
in Australia
.
(Dionaea muscipula). In a review of the research on the evolution of the Venus flytrap from sticky-leaved ancestors, botanists Thomas Gibson and Donald Waller use D. falconeri as an example of a sticky-leaved species that shares many characteristics with the Venus flytrap, such as a wide petiole
and lamina
, and faces the same challenge of prey escape that the snap trap of the Venus flytrap evolved in response to.
Drosera falconeri is a tropical perennial plant
with a rosette
body plan
that is common for the genus Drosera. Deciduous
leaves lay flat against the soil. Leaves are usually smaller at anthesis
(flowering), but increase as the growing season progresses. Typical reniform
lamina
at maturity are 1.5 cm (0.590551181102362 in) long and 2 cm (0.78740157480315 in) wide, with leaves on older specimens being as wide as 3 cm (1.2 in). It is unique in the subgenus because of its large leaves that are typically flat against the soil. Retentive mucilage
-producing glands held on stalks - structures known as tentacle
s - appear on the margin of the lamina with shorter glands in the center of the leaf. The abaxial (underside) surface of the leaf is noticeably veined and sparsely covered with non-glandular white hairs. Petioles are oblanceolate
and usually 10 mm long with varying widths: 2 mm near the center of the rosette, 3.5 mm near the center of the petiole, and 3 mm at the point of attachment to the lamina. The upper surface of the petiole is glabrous, but the margins and lower surface possess hairs similar to those of the abaxial leaf surface.
One or two racemose inflorescence
s are produced per plant and are usually 8 cm (3.1 in) long. Approximately 12 flowers are found on one inflorescence with each white or pink flower held on a 3–5 mm long pedicel
. The scape
, inflorescence, and sepal
s are sparsely covered in white hairs. Flowers are composed of elliptic 3 mm long by 1.8 mm wide sepals, 7 mm long by 4 mm wide petals, five 2.7 mm long white stamen
s that produce orange anthers and pollen, a 1.1 mm diameter ovary
with bilobed carpels
and three white 2.5 mm long styles that are extensively branched toward the apex with terminal white stigmas
. It typically flowers from November to December with only one flower open at a time, lasting for just one day whether it was pollinated or not.
In the dry season
the leaves die back and the plant survives by forming a bulb-like structure of tightly-packed leaf bases just below the soil's surface. This adaptation helps it avoid desiccation during the dry season. The hard clay soils acts as insulation; all other species in subgenus Lasiocephala use dense white hairs for insulation. Dormancy is typically broken with the first rains of the wet season and growth proceeds quickly. New growth, such as a new fibrous root system, new leaves, and the inflorescence, must build up reserves and set seed; a short wet season and sudden drought may cut the growing season considerably. New roots are white and fleshy, mostly serving as a water storage organ, while older roots become thinner and mostly anchor the plant.
Its diploid chromosome number is 2n = 12.
complex, which includes the species in the subgenus Lasiocephala. Hybridisation is rare in the wild, however, because the soil types specific to individual parent species do not converge often. The first natural hybrid to be discovered was the product of D. falconeri and D. dilatato-petiolaris
, later given the nomen nudum
D. dilaconeri in 1991 by E. Westphal. Seed from this hybrid has proved to be viable which is an unusual characteristic for Drosera hybrids. Approximately four recognisable forms of this hybrid can be found in the wild. The characteristics favour one parent species or the other: some forms are smaller at 4–5 cm (1.6–2 in) in diameter while others can be up to 10 cm (3.9 in) in diameter, the leaf varies in size, and some hybrids will form clumps by producing plantlets like D. dilatato-petiolaris does while others will remain isolated. Drosera falconeri also hybridises with D. petiolaris; this hybrid was given the nomen nudum D. petioconeri by Westphal in 1991.
Artificial hybrids involving D. falconeri have also been produced and cultivated, including a complex hybrid: (D. falconeri × D. ordensis
) × (D. darwinensis
× D. falconeri).
and Berry Springs
regions and on Melville Island.
While most carnivorous plants are calcifuge
s that cannot tolerate alkaline soils, D. falconeri grows on calcareous
sandy soils with high pH
values. In the first account of this species' habitat, the soil pH at the site was recorded as pH 8. At the site where D. falconeri was first discovered, tall dense grass covered the small population.
. Tsang then sent specimens on to Allen Lowrie
and Bill Lavarack, a botanist with the Queensland National Parks. Tsang also prepared a short announcement of this new species published in the June 1980 issue of the Carnivorous Plant Newsletter
, giving a brief description and suggesting the specific epithet honour Mr Falconer as its discoverer. It was not until 1984 that Katsuhiko Kondo provided the formal description required under the rules of the International Code of Botanical Nomenclature in an article that described three new species in the D. petiolaris complex. The holotype
specimen is Kondo 2227 held at the Herbarium
of Faculty of Arts and Sciences at Hiroshima University
. Isotype specimens, those that are duplicates of the holotype, were distributed to several herbaria, including those at the University of North Carolina
, the New York Botanical Garden
, the National Herbarium of New South Wales
, and the Queensland Herbarium
.
The species was only known from a single location, the description of which vaguely positioned it along the Finniss River, a river that is nearly 100 km (62.1 mi) long. Tsang died in 1984 and it was feared that the exact location of the known population was lost with him. Further field studies, however, produced several new sites.
Its alliance with the D. petiolaris complex in subgenus
Lasiocephala
was suspected from its earliest description by Peter Tsang, who noted similarities in their dormant bud and root structures. This assessment has been confirmed by further analysis by other botanists.
It is considered to be a difficult species to grow in cultivation. During its seasonal dormancy, D. falconeri produces a tight rosette of leaves that resembles a hibernating bud. It is often grown in a peat
:sand or perlite
soil. Plants can be vegetatively propagated
by submerging leaf pullings in pure water. Under the Australian botanist Allen Lowrie
's growing conditions, species in subgenus Lasiocephala grow year-round without dormancy. Lowrie also notes that these species produce deep red foliage in the wild, a characteristic that is lost in cultivation when plants retain a greener appearance presumably caused by lower light intensities.
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...
in the genus Drosera. It is endemic to the Northern Territory
Northern Territory
The Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...
in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
Description
Drosera falconeri superficially resembles the Venus flytrapVenus Flytrap
The Venus Flytrap , Dionaea muscipula, is a carnivorous plant that catches and digests animal prey—mostly insects and arachnids. Its trapping structure is formed by the terminal portion of each of the plant's leaves and is triggered by tiny hairs on their inner surfaces...
(Dionaea muscipula). In a review of the research on the evolution of the Venus flytrap from sticky-leaved ancestors, botanists Thomas Gibson and Donald Waller use D. falconeri as an example of a sticky-leaved species that shares many characteristics with the Venus flytrap, such as a wide petiole
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
and lamina
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
, and faces the same challenge of prey escape that the snap trap of the Venus flytrap evolved in response to.
Drosera falconeri is a tropical perennial plant
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
with a rosette
Rosette (botany)
In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.Though rosettes usually sit near the soil, their structure is an example of a modified stem.-Function:...
body plan
Body plan
A body plan is the blueprint for the way the body of an organism is laid out. An organism's symmetry, its number of body segments and number of limbs are all aspects of its body plan...
that is common for the genus Drosera. Deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
leaves lay flat against the soil. Leaves are usually smaller at anthesis
Anthesis
Anthesis is the period during which a flower is fully open and functional. It may also refer to the onset of that period.The onset of anthesis is spectacular in some species. In Banksia species, for example, anthesis involves the extension of the style far beyond the upper perianth parts...
(flowering), but increase as the growing season progresses. Typical reniform
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...
lamina
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
at maturity are 1.5 cm (0.590551181102362 in) long and 2 cm (0.78740157480315 in) wide, with leaves on older specimens being as wide as 3 cm (1.2 in). It is unique in the subgenus because of its large leaves that are typically flat against the soil. Retentive mucilage
Mucilage
Mucilage is a thick, gluey substance produced by most plants and some microorganisms. It is a polar glycoprotein and an exopolysaccharide.It occurs in various parts of nearly all classes of plant, usually in relatively small percentages, and is frequently associated with other substances, such as...
-producing glands held on stalks - structures known as tentacle
Tentacle
A tentacle or bothrium is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like...
s - appear on the margin of the lamina with shorter glands in the center of the leaf. The abaxial (underside) surface of the leaf is noticeably veined and sparsely covered with non-glandular white hairs. Petioles are oblanceolate
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...
and usually 10 mm long with varying widths: 2 mm near the center of the rosette, 3.5 mm near the center of the petiole, and 3 mm at the point of attachment to the lamina. The upper surface of the petiole is glabrous, but the margins and lower surface possess hairs similar to those of the abaxial leaf surface.
One or two racemose inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
s are produced per plant and are usually 8 cm (3.1 in) long. Approximately 12 flowers are found on one inflorescence with each white or pink flower held on a 3–5 mm long 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....
. The scape
Scape (botany)
In botany, scapes are leafless flowering stems that rise from the ground. Scapes can have a single flower or many flowers, depending on the species....
, inflorescence, and sepal
Sepal
A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...
s are sparsely covered in white hairs. Flowers are composed of elliptic 3 mm long by 1.8 mm wide sepals, 7 mm long by 4 mm wide petals, five 2.7 mm long white stamen
Stamen
The stamen is the pollen producing reproductive organ of a flower...
s that produce orange anthers and pollen, a 1.1 mm diameter ovary
Ovary (plants)
In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule and is located above or below or at the point of connection with the base of the petals and sepals...
with bilobed carpels
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...
and three white 2.5 mm long styles that are extensively branched toward the apex with terminal white stigmas
Stigma (botany)
The stigma is the receptive tip of a carpel, or of several fused carpels, in the gynoecium of a flower. The stigma receives pollen at pollination and it is on the stigma that the pollen grain germinates. The stigma is adapted to catch and trap pollen with various hairs, flaps, or sculpturings...
. It typically flowers from November to December with only one flower open at a time, lasting for just one day whether it was pollinated or not.
In the dry season
Dry season
The dry season is a term commonly used when describing the weather in the tropics. The weather in the tropics is dominated by the tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year...
the leaves die back and the plant survives by forming a bulb-like structure of tightly-packed leaf bases just below the soil's surface. This adaptation helps it avoid desiccation during the dry season. The hard clay soils acts as insulation; all other species in subgenus Lasiocephala use dense white hairs for insulation. Dormancy is typically broken with the first rains of the wet season and growth proceeds quickly. New growth, such as a new fibrous root system, new leaves, and the inflorescence, must build up reserves and set seed; a short wet season and sudden drought may cut the growing season considerably. New roots are white and fleshy, mostly serving as a water storage organ, while older roots become thinner and mostly anchor the plant.
Its diploid chromosome number is 2n = 12.
Hybrids
It can readily hybridise with other species in the D. petiolarisDrosera petiolaris
Drosera petiolaris is a carnivorous plant in the genus Drosera and is the eponymous species of the petiolaris species complex, which mostly refers to the entire subgenus Lasiocephala...
complex, which includes the species in the subgenus Lasiocephala. Hybridisation is rare in the wild, however, because the soil types specific to individual parent species do not converge often. The first natural hybrid to be discovered was the product of D. falconeri and D. dilatato-petiolaris
Drosera dilatato-petiolaris
Drosera dilatato-petiolaris is a carnivorous plant in the genus Drosera and is endemic to Australia, being found in both Western Australia and the Northern Territory. Its leaves are arranged in a rosette and commonly produces plantlets, eventually forming large clumps that can be over across...
, later given the nomen nudum
Nomen nudum
The phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...
D. dilaconeri in 1991 by E. Westphal. Seed from this hybrid has proved to be viable which is an unusual characteristic for Drosera hybrids. Approximately four recognisable forms of this hybrid can be found in the wild. The characteristics favour one parent species or the other: some forms are smaller at 4–5 cm (1.6–2 in) in diameter while others can be up to 10 cm (3.9 in) in diameter, the leaf varies in size, and some hybrids will form clumps by producing plantlets like D. dilatato-petiolaris does while others will remain isolated. Drosera falconeri also hybridises with D. petiolaris; this hybrid was given the nomen nudum D. petioconeri by Westphal in 1991.
Artificial hybrids involving D. falconeri have also been produced and cultivated, including a complex hybrid: (D. falconeri × D. ordensis
Drosera ordensis
Drosera ordensis is a species of sundew, native to Australia and part of the "petiolaris complex" of sundews making up the subgenus Lasiocephala. Compared to many petiolaris sundews, it has wide petioles, which are densely covered in silvery hairs...
) × (D. darwinensis
Drosera darwinensis
Drosera darwinensis is a perennial carnivorous plant in the genus Drosera that is endemic to the Northern Territory. Its leaves are arranged in a rosette with one rosette emerging from the root stock. It produces pink or white flowers from December to April. Drosera darwinensis grows in clayey...
× D. falconeri).
Distribution and ecology
Drosera falconeri is common throughout the northern coastal areas of the Northern Territory in Australia. It was originally located along the Finniss River in alkaline sandy soils. It is found growing in the grey silty clay soils in the PalmerstonPalmerston, Northern Territory
Palmerston is a planned satellite city of Darwin, the capital and largest city in Australia's Northern Territory. Palmerston is situated near Darwin Harbour and has an urban population of 23,614 on the 2006 Census night and making it the second largest city in the territory...
and Berry Springs
Berry Springs, Northern Territory
Berry Springs is an outer suburban area in Darwin. The name "Berry Springs" derived from "Berry Creek", named by Goyder in 1870, after his Chief Draftsman, Edwin S Berry....
regions and on Melville Island.
While most carnivorous plants are calcifuge
Calcifuge
A calcifuge is a plant that does not tolerate alkaline soil. The word is derived from the Latin 'to flee from chalk'. These plants are also described as ericaceous, as the prototypical calcifuge is the genus Erica...
s that cannot tolerate alkaline soils, D. falconeri grows on calcareous
Calcareous
Calcareous is an adjective meaning mostly or partly composed of calcium carbonate, in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.-In zoology:...
sandy soils with high pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
values. In the first account of this species' habitat, the soil pH at the site was recorded as pH 8. At the site where D. falconeri was first discovered, tall dense grass covered the small population.
Botanical history and taxonomy
Drosera falconeri was first discovered by a Mr Falconer in 1980 along the Finniss River in the Northern Territory. Falconer was collecting plants and tropical fish for Peter Tsang, a carnivorous plant enthusiast living in QueenslandQueensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
. Tsang then sent specimens on to Allen Lowrie
Allen Lowrie
Allen Lowrie is a West Australian botanist. He is living in Duncraig, a Perth suburb, is married and has two daughters.Lowrie, originally a businessman and inventor, got in contact with the carnivorous flora of western Australia in the late sixties and worked on it as an amateur...
and Bill Lavarack, a botanist with the Queensland National Parks. Tsang also prepared a short announcement of this new species published in the June 1980 issue of the Carnivorous Plant Newsletter
Carnivorous Plant Newsletter
The Carnivorous Plant Newsletter is the official publication of the International Carnivorous Plant Society , the largest such organization in the world.-History and editorship:...
, giving a brief description and suggesting the specific epithet honour Mr Falconer as its discoverer. It was not until 1984 that Katsuhiko Kondo provided the formal description required under the rules of the International Code of Botanical Nomenclature in an article that described three new species in the D. petiolaris complex. The holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
specimen is Kondo 2227 held at the Herbarium
Herbarium
In botany, a herbarium – sometimes known by the Anglicized term herbar – is a collection of preserved plant specimens. These specimens may be whole plants or plant parts: these will usually be in a dried form, mounted on a sheet, but depending upon the material may also be kept in...
of Faculty of Arts and Sciences at Hiroshima University
Hiroshima University
, located in the Japanese cities of Higashihiroshima and Hiroshima, was established 1949 by the merger of a number of national educational institutions.-History:Under the National School Establishment Law, Hiroshima University was established on May 31, 1949...
. Isotype specimens, those that are duplicates of the holotype, were distributed to several herbaria, including those at the University of North Carolina
University of North Carolina
Chartered in 1789, the University of North Carolina was one of the first public universities in the United States and the only one to graduate students in the eighteenth century...
, the New York Botanical Garden
New York Botanical Garden
- See also :* Education in New York City* List of botanical gardens in the United States* List of museums and cultural institutions in New York City- External links :* official website** blog*...
, the National Herbarium of New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
, and the Queensland Herbarium
Queensland Herbarium
The Queensland Herbarium is situated at the Brisbane Botanic Gardens, Mount Coot-tha, in Brisbane, Queensland, Australia. It is part of Queensland’s Environmental Protection Agency...
.
The species was only known from a single location, the description of which vaguely positioned it along the Finniss River, a river that is nearly 100 km (62.1 mi) long. Tsang died in 1984 and it was feared that the exact location of the known population was lost with him. Further field studies, however, produced several new sites.
Its alliance with the D. petiolaris complex in subgenus
Subgenus
In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...
Lasiocephala
Drosera subg. Lasiocephala
Drosera subg. Lasiocephala, sometimes collectively known as the petiolaris-complex, is a subgenus of 14 species in the genus Drosera. These species are distinguished by their subpeltate to peltate lamina....
was suspected from its earliest description by Peter Tsang, who noted similarities in their dormant bud and root structures. This assessment has been confirmed by further analysis by other botanists.
Cultivation
Drosera falconeri was first cultivated by Peter Tsang shortly after its initial discovery. He then sent living specimens on to others to establish the new species in cultivation.It is considered to be a difficult species to grow in cultivation. During its seasonal dormancy, D. falconeri produces a tight rosette of leaves that resembles a hibernating bud. It is often grown in a peat
Peat
Peat is an accumulation of partially decayed vegetation matter or histosol. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world...
:sand or perlite
Perlite
Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently...
soil. Plants can be vegetatively propagated
Vegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...
by submerging leaf pullings in pure water. Under the Australian botanist Allen Lowrie
Allen Lowrie
Allen Lowrie is a West Australian botanist. He is living in Duncraig, a Perth suburb, is married and has two daughters.Lowrie, originally a businessman and inventor, got in contact with the carnivorous flora of western Australia in the late sixties and worked on it as an amateur...
's growing conditions, species in subgenus Lasiocephala grow year-round without dormancy. Lowrie also notes that these species produce deep red foliage in the wild, a characteristic that is lost in cultivation when plants retain a greener appearance presumably caused by lower light intensities.
See also
- List of Drosera species
- Taxonomy of Drosera