Socratea exorrhiza
Encyclopedia
Socratea exorrhiza, the Walking Palm or Cashapona, is a palm
native to rainforest
s in tropical Central
and South America
. It can grow to 25 meters in height, with a stem diameter of up to 17 cm. It has unusual stilt roots, the function of which has been debated. Many species of epiphyte
have been found growing on the palms. The palm is pollinated by beetles, and various organisms consume its seeds or seedlings.
y areas of forest. No evidence exists that stilt roots are in fact an adaptation to flooding, and alternative functions for them have been suggested. Bodley suggested in 1980 that they in fact allow the palm to "walk" away from the point of germination if another tree falls on the seedling and knocks it over. If such an event occurs then the palm produces new vertical stilt roots and can then right itself, the original roots rotting away. Radford writes in the December 2009 Skeptical Inquirer
that "As interesting as it would be to think that when no one is around trees walk the rainforest floor, it is a mere myth", and cites two detailed studies that came to this conclusion. Other advantages of stilt roots over normal roots have since been proposed. Swaine proposed in 1983 that they allow the palm to colonise areas where there is much debris (for example, dead logs) as they can avoid it by moving their roots. Hartshorn suggested in 1983 that stilt roots allow the palm to grow upwards to reach light without having to increase the diameter of the stem. The roots make the palm more stable and therefore allow it to grow taller and more quickly than if they did not possess them. They also allow the palm to invest less biomass in underground roots than other palms, therefore leaving more energy to be used in growing above ground. It was also thought that the roots may confer an advantage when the palm is growing on a slope, but no evidence has been found that this is the case.
Iriartea ventricosa has similar roots to S. exorrhiza.
have been found to grow on S. exorrhiza. A study of 118 individual trees in Panama
found 66 species from 15 families on them. Bryophytes covered up to 30% of the stems, and the relative coverage increased as the stem diameter increased. Around half of the trees studied had vascular
epiphytes growing on them. Up to 85 individuals from 12 different species were found on one palm, and another tree was colonised by a total of 16 different species. The most common epiphytes were three species of fern, Ananthacorus angustifolius, Elaphoglossum sporadolepis and Dicranoglossum panamense, altogether accounting for 30% of all the individuals recorded. Other common species, representing more than 5% of the individuals found, included Scaphyglottis longicaulis
(Orchidaceae
), Philodendron schottianum (Araceae
) and Guzmania subcorymbosa
(Bromeliaceae
). Almost half of the species recorded were rare, however, with only between 1 and 3 individuals being recorded on all of the palms. A clear vertical distribution was found between different species: some grew in the understory, other in the midstory and others in the canopy. Trees with epiphytes were found to be significantly larger than those without. This suggests that the palms must reach a certain age before they are colonised; for example, it is estimated that palms must be 20 years old before they are colonised by vascular epiphytes.
s and more stoma
ta than those that grow in the shade.
pollinated
, being frequently visited by species of Phyllotrox (Derelomini) and Mystrops (Nitidulidae). Seeds weigh around 3.5 g and are around 2 cm long and 1.5 cm wide, only around 45% of them germinate and around one quarter of these die.
. The roots are also cooked in water to make a tea to treat hepatitis
. The yellow fruits are edible.
Arecaceae
Arecaceae or Palmae , are a family of flowering plants, the only family in the monocot order Arecales. There are roughly 202 currently known genera with around 2600 species, most of which are restricted to tropical, subtropical, and warm temperate climates...
native to rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
s in tropical Central
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
and 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...
. It can grow to 25 meters in height, with a stem diameter of up to 17 cm. It has unusual stilt roots, the function of which has been debated. Many species of epiphyte
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
have been found growing on the palms. The palm is pollinated by beetles, and various organisms consume its seeds or seedlings.
Function of stilt roots
Corner in 1961 hypothesised that the unusual stilt roots of S. exorrhiza were an adaptation to allow the palm to grow in swampSwamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
y areas of forest. No evidence exists that stilt roots are in fact an adaptation to flooding, and alternative functions for them have been suggested. Bodley suggested in 1980 that they in fact allow the palm to "walk" away from the point of germination if another tree falls on the seedling and knocks it over. If such an event occurs then the palm produces new vertical stilt roots and can then right itself, the original roots rotting away. Radford writes in the December 2009 Skeptical Inquirer
Skeptical Inquirer
The Skeptical Inquirer is a bimonthly American magazine published by the Committee for Skeptical Inquiry with the subtitle: The magazine for science and reason....
that "As interesting as it would be to think that when no one is around trees walk the rainforest floor, it is a mere myth", and cites two detailed studies that came to this conclusion. Other advantages of stilt roots over normal roots have since been proposed. Swaine proposed in 1983 that they allow the palm to colonise areas where there is much debris (for example, dead logs) as they can avoid it by moving their roots. Hartshorn suggested in 1983 that stilt roots allow the palm to grow upwards to reach light without having to increase the diameter of the stem. The roots make the palm more stable and therefore allow it to grow taller and more quickly than if they did not possess them. They also allow the palm to invest less biomass in underground roots than other palms, therefore leaving more energy to be used in growing above ground. It was also thought that the roots may confer an advantage when the palm is growing on a slope, but no evidence has been found that this is the case.
Iriartea ventricosa has similar roots to S. exorrhiza.
Epiphytes
Many different species of epiphyteEpiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
have been found to grow on S. exorrhiza. A study of 118 individual trees in Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
found 66 species from 15 families on them. Bryophytes covered up to 30% of the stems, and the relative coverage increased as the stem diameter increased. Around half of the trees studied had vascular
Vascular plant
Vascular plants are those plants that have lignified tissues for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the clubmosses, Equisetum, ferns, gymnosperms and angiosperms...
epiphytes growing on them. Up to 85 individuals from 12 different species were found on one palm, and another tree was colonised by a total of 16 different species. The most common epiphytes were three species of fern, Ananthacorus angustifolius, Elaphoglossum sporadolepis and Dicranoglossum panamense, altogether accounting for 30% of all the individuals recorded. Other common species, representing more than 5% of the individuals found, included Scaphyglottis longicaulis
Scaphyglottis longicaulis
Scaphyglottis longicaulis is a species of orchid found from Central America to northwestern Ecuador. It has been found as an epiphyte growing on Socratea exorrhiza in Panama.-References and external links:...
(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,...
), Philodendron schottianum (Araceae
Araceae
Araceae are a family of monocotyledonous flowering plants in which flowers are borne on a type of inflorescence called a spadix. The spadix is usually accompanied by, and sometimes partially enclosed in, a spathe or leaf-like bract. Also known as the Arum family, members are often colloquially...
) and Guzmania subcorymbosa
Guzmania subcorymbosa
Guzmania subcorymbosa is a species of the genus Guzmania. This species is native to Costa Rica.-References:* retrieved 3 November 2009...
(Bromeliaceae
Bromeliaceae
Bromeliaceae is a family of monocot flowering plants of around 3,170 species native mainly to the tropical Americas, with a few species found in the American subtropics and one in tropical west Africa, Pitcairnia feliciana...
). Almost half of the species recorded were rare, however, with only between 1 and 3 individuals being recorded on all of the palms. A clear vertical distribution was found between different species: some grew in the understory, other in the midstory and others in the canopy. Trees with epiphytes were found to be significantly larger than those without. This suggests that the palms must reach a certain age before they are colonised; for example, it is estimated that palms must be 20 years old before they are colonised by vascular epiphytes.
Leaf morphology
Leaves of S. exorrhiza that grow in the sun are thicker, have more trichomeTrichome
Trichomes are fine outgrowths or appendages on plants and certain protists. These are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae.- Algal trichomes :...
s and more stoma
Stoma
In botany, a stoma is a pore, found in the leaf and stem epidermis that is used forgas exchange. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that are responsible for regulating the size of the opening...
ta than those that grow in the shade.
Predators
White-lipped peccaries predate a large proportion of the seeds of S. exorrhiza and play an important role in limiting their population.Reproduction
S. exorrhiza flowers mostly during the dry season and is considered to be beetleBeetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
pollinated
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...
, being frequently visited by species of Phyllotrox (Derelomini) and Mystrops (Nitidulidae). Seeds weigh around 3.5 g and are around 2 cm long and 1.5 cm wide, only around 45% of them germinate and around one quarter of these die.
Uses
The trunk is used in the construction of houses and other structures, as well as hunting spears. It is usually split lengthwise before it is used, but it can also be hollowed out and used as a tube. The inner parts of the stilt roots are used as a male aphrodisiacAphrodisiac
An aphrodisiac is a substance that increases sexual desire. The name comes from Aphrodite, the Greek goddess of sexuality and love. Throughout history, many foods, drinks, and behaviors have had a reputation for making sex more attainable and/or pleasurable...
. The roots are also cooked in water to make a tea to treat hepatitis
Hepatitis
Hepatitis is a medical condition defined by the inflammation of the liver and characterized by the presence of inflammatory cells in the tissue of the organ. The name is from the Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...
. The yellow fruits are edible.