Plectocomiopsis
Encyclopedia
Plectocomiopsis is a dioecious genus
of flowering plant
in the palm
family found in Thailand
, Malaysia, Borneo
and Sumatra
. Hapaxanthic and armed with spines, they are a climbing rattan
, closely related to the Myrialepis
palms. The name is Greek
for "similar to Plectocomia
", another close relative.
are undivided or with few segments, in maturity becoming pinnate and cirrate with a tubular, unarmed or sparsely armed, scaly leaf sheath. Ocreas present, entire or becoming tattered. The petiole, when present, and the proximal end of the rachis are deeply channeled and spiny; the cirrus and distal end of the rachis are armed with regularly arranged reflexed climbing spines. The single fold, lanceolate leaflets may be few to numerous, usually with armed margins and caducous scales, with conspicuous midribs and transverse veinlets.
The inflorescence
is produced at the top of the stem amongst the most distal, often reduced leaves, axis adnate to the internode and emerging from the leaf sheath mouth. The peduncle is short, the prophyll is tubular and two-keeled, peduncular bracts usually absent, and the rachis is much longer than the peduncle. The rachis bracts are tubular and more or less distichous, each subtending a horizontal or pendulous first order branch which features basal, tubular bracts with triangular limbs carrying monopodial flower
clusters. In P. corneri the inflorescence is branched to three orders instead of two, with flowers borne on the axes of all orders.
The male flowers are arranged in clusters of up to 32, each flower held in a cuplike rachilla bract with a two-keeled bracteole. The calyx is thick, leathery and tubular, with three lobes, and abaxially covered in scaly trichomes; the corolla is similar, with two distal splits forming three triangle shaped lobes, also bearing scales. The six stamens are laterally fused forming a tube which is tipped by six free, reflexed filaments with short, oblong anthers. The pollen
is disculate and elliptic with tectate exine; pistillode minute.
Female flowers are usually borne in clusters of two to four but may be solitary, and, like the male's, are carried in cuplike bracts with two-keeled bracteoles, with the occasional barely developed second bracteole. The calyx is also thick and leathery, thrice lobed and scaly, usually persistent into fruit; corolla leathery, scaly, with three lobes. The staminodial ring bears six short lobes and sagging, empty anthers; gynoecium egg-shaped to cylindrical, the apical stigmas becoming scaly nearing antithesis. Three incomplete locules are present, each bearing one antropous, basally attached ovule. The fruit
has one, rarely two seed
s, covered in persistent perianth whorls, and stigmatic apical remains. The epicarp is matted in irregular vertical rows of reflexed scales, with a thin mesocarp and an undifferentiated endocarp. The seed
is basally attached, spherical, usually depressed, with a thick sarcoesta, a homogeneous endosperm and a basal embryo
.
inhabitants, the former in Borneo, the latter in Malaysia. P. corneri and P. mira are Dipterocarp forest
dwellers to 700 m, and P. geminiflora is distributed through a variety of tropical forest types to 1200 m.
; villagers regard some of the others as edible and some as poisonous.
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...
of flowering plant
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
in the palm
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...
family found in Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
, Malaysia, Borneo
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
and Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
. Hapaxanthic and armed with spines, they are a climbing rattan
Rattan
Rattan is the name for the roughly 600 species of palms in the tribe Calameae, native to tropical regions of Africa, Asia and Australasia.- Structure :...
, closely related to the Myrialepis
Myrialepis
Myrialepis is a monotypic genus of flowering plant in the palm family native to Southeast Asia, where the only species Myrialepis paradoxa is colloquially called rotan kertong, or simply rattan...
palms. The name is Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
for "similar to Plectocomia
Plectocomia
Plectocomia is a genus of flowering plant in the Arecaceae family. It contains at least the following species:* Plectocomia assamica* Plectocomia elongata* Plectocomia himalayana* Plectocomia microstachys* Plectocomia perreana...
", another close relative.
Description
The stems are small, densely clustering, spiny, and high climbing with long internodes and conspicuous scars. Young leavesLeaf
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....
are undivided or with few segments, in maturity becoming pinnate and cirrate with a tubular, unarmed or sparsely armed, scaly leaf sheath. Ocreas present, entire or becoming tattered. The petiole, when present, and the proximal end of the rachis are deeply channeled and spiny; the cirrus and distal end of the rachis are armed with regularly arranged reflexed climbing spines. The single fold, lanceolate leaflets may be few to numerous, usually with armed margins and caducous scales, with conspicuous midribs and transverse veinlets.
The 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...
is produced at the top of the stem amongst the most distal, often reduced leaves, axis adnate to the internode and emerging from the leaf sheath mouth. The peduncle is short, the prophyll is tubular and two-keeled, peduncular bracts usually absent, and the rachis is much longer than the peduncle. The rachis bracts are tubular and more or less distichous, each subtending a horizontal or pendulous first order branch which features basal, tubular bracts with triangular limbs carrying monopodial 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...
clusters. In P. corneri the inflorescence is branched to three orders instead of two, with flowers borne on the axes of all orders.
The male flowers are arranged in clusters of up to 32, each flower held in a cuplike rachilla bract with a two-keeled bracteole. The calyx is thick, leathery and tubular, with three lobes, and abaxially covered in scaly trichomes; the corolla is similar, with two distal splits forming three triangle shaped lobes, also bearing scales. The six stamens are laterally fused forming a tube which is tipped by six free, reflexed filaments with short, oblong anthers. The pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
is disculate and elliptic with tectate exine; pistillode minute.
Female flowers are usually borne in clusters of two to four but may be solitary, and, like the male's, are carried in cuplike bracts with two-keeled bracteoles, with the occasional barely developed second bracteole. The calyx is also thick and leathery, thrice lobed and scaly, usually persistent into fruit; corolla leathery, scaly, with three lobes. The staminodial ring bears six short lobes and sagging, empty anthers; gynoecium egg-shaped to cylindrical, the apical stigmas becoming scaly nearing antithesis. Three incomplete locules are present, each bearing one antropous, basally attached ovule. The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
has one, rarely two seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s, covered in persistent perianth whorls, and stigmatic apical remains. The epicarp is matted in irregular vertical rows of reflexed scales, with a thin mesocarp and an undifferentiated endocarp. The seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
is basally attached, spherical, usually depressed, with a thick sarcoesta, a homogeneous endosperm and a basal embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
.
Distribution and habitat
P. triquetra and P. wrayi are low land peat swamp forestPeat swamp forest
Peat swamp forests are tropical moist forests where waterlogged soils prevent dead leaves and wood from fully decomposing, which over time creates a thick layer of acidic peat...
inhabitants, the former in Borneo, the latter in Malaysia. P. corneri and P. mira are Dipterocarp forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...
dwellers to 700 m, and P. geminiflora is distributed through a variety of tropical forest types to 1200 m.
Cultivation and uses
The Plectocomiopsis species are not usually cultivated, being extremely spiny and requiring particular tropical conditions. In their natural range they are used in basketry, however their fragile nature prevents them from being a common rattan source. The palm heart of P. geminiflora, despite its bitter taste, is regarded as a delicacy in BorneoBorneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
; villagers regard some of the others as edible and some as poisonous.