Plectocomia

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Plectocomia
Plectocomia elongata

Plectocomia elongata

Systematics
Class : Bedecktsamer (Magnoliopsida)
Monocots
Commelinids
Order : Palm- like arecales
Family : Palm family (Arecaceae)
Genre : Plectocomia
Scientific name
Plectocomia
Mart. ex flower

Plectocomia is a climbing palm genus native to Asia. The inflorescences have long, hanging side axes of the first order, the individual flower-bearing side axes of the second order are surrounded by conspicuous, boat-shaped bracts.

features

The representatives are multi-stemmed, high-climbing rattan palms. They are hapaxanth and diocesan . The trunk has long internodes and noticeable scars. In the lower area of ​​the internodes there are sometimes numerous, bulbil-like shoots. After cutting the trunk, this clear rubber sap exudes. The trunk has a soft pith , which is why the species are not used for rattan furniture .

The number of chromosomes is unknown (as of 2008).

leaves

The leaves of adult palm trees are large, pinnate and have a tendril . The leaf sheath is tubular and reinforced to varying degrees. An ochrea is missing. The petiole may be missing. Like the lower part of the Rhachis , it is deeply furrowed and reinforced to varying degrees. The tendril and the upper part of the rachis are regularly covered with groups of large, backward-facing spines. The numerous leaflets are simply folded, with entire margins, mostly lanceolate.

Inflorescences

The inflorescences are formed simultaneously in the axils of the two to 20 most distal, often reduced leaves. The inflorescence axis is significantly longer than the stalk. The bracts on the inflorescence axis are distich (two rows), each has a hanging side axis of the first order. There are three to 20 of these, rarely more. Each has a basal, tubular two-keeled cover sheet and one to several empty tubular bracts. The other bracts are very noticeable. They are distant, are initially tubular and tear open almost to the tip before they bloom. They partially or completely enclose the rachilla (flower-bearing axis). The bracts are thin to very thick, leathery or partially lignified. The rachillae are unbranched, slender and have two to ten flowers in female inflorescences, in male two to about 100. The male groups are sometimes in clear groups of two (dyads), often the arrangement in dyads is overlaid by crowded together and long inflorescences.

blossoms

The male flowers have a short tubular calyx with three short lobes. The crown is tubular in the lower area and has three triangular to lanceolate lobes. The usually six, rarely twelve stamens are sometimes fused with their stamens at the base. They stand at the mouth of the corolla tube. The anthers are usually long. The rudiment of the stamp is very small or missing entirely. The pollen is ellipsoidal and bisymmetrical, the germ openings are equatorial bisulcat. The longest axis measures 26 to 49 micrometers.

The female flowers are solitary, often stalked with a two-keeled bracteole on the stem. The calyx is short tubular and has three short to very long lobes. The crown is also tubular and has three narrow to wide triangular lobes. The crown is slightly to significantly longer than the calyx. The six staminodes have flat stamens and empty anthers. The gynoecium is round, covered with scales, has three usually very long scars and sometimes a clearly distinct style . The three fruit compartments are incomplete, have three ovules that are basal and anatropic.

Fruits and seeds

The fruit is usually single, rarely two or three seeds. The exocarp is covered with vertical rows of backward-facing scales. The tips of the scales often point upwards. The mesocarp is thin and fibrous, the endocarp is not differentiated. The seed sits near the base, the sarcotesta is thick but not juicy. The endosperm is homogeneous.

ecology

As visitors to the highly fragrant male flowers of plectocomia turn fell diana were bees and beetles ( Nitidulidae , Staphylinidae ) were observed. Nothing is known about the spread of the fruit.

Distribution and locations

The area extends from the Himalayas, southern China and Hainan through Burma and Indochina to the Sunda Shelf and the Philippines. The genus does not occur east of the Wallace line .

The most widespread and best known species are Plectocomia elongata and Plectocomia mulleri . Both grow from sea level to 2000 m above sea level. The former usually grows in disturbed locations on poor soils, the latter also in swamp forests and heather forests (Kerangas).

Systematics

The genus Plectocomia Mart. & Blume is placed within the family Arecaceae in the subfamily Calamoideae , Tribe Calameae . Together with the genera Myrialepis and Plectocomiopsis, it forms the subtribe Plectocomiinae . The relationships between the three genera are unclear. Plectocomia is monophyletic .

The Royal Botanic Gardens, Kew's World Checklist of Selected Plant Families recognizes the following species:

supporting documents

  • John Dransfield, Natalie W. Uhl, Conny B. Asmussen, William J. Baker, Madeline M. Harley, Carl E. Lewis: Genera Palmarum. The Evolution and Classification of Palms . Second edition, Royal Botanic Gardens, Kew 2008, ISBN 978-1-84246-182-2 , pp. 182-185.

Individual evidence

  1. ↑ a b c Rafaël Govaerts (Ed.): Plectocomia. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved August 2, 2018.
  2. ↑ a b c gou ye teng shu: Plectocomia In: Flora of China . Volume 23, page 134. [1]

Web links

  • Plectocomia on the homepage of the Fairchild Tropical Botanic Garden