Korthalsia

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Korthalsia
Korthalsia zippelii

Korthalsia zippelii

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

Korthalsia is a palm genus native to Asia. It is named in honor of the Dutch botanist Pieter Willem Korthals (1807-1892).

features

The representatives are multi-stemmed, high-climbing rattan palms that branch out. The single flowers are hermaphroditic, the plants only flower once ( hapaxanth ). The trunk is often occupied with the inner epidermis of the leaf sheaths. The internodes are long and the nodal scars are often uneven. The branching is dichotomous.

The number of chromosomes is 2n = 32.

leaves

The leaves are pinnate and have a tendril at the end . The leaf sheath is tubular, unarmed and reinforced, as well as richly covered with scales and hair. The ochrea is always distinct, either tightly fitting or expanded to a loose funnel-shaped fiber network. The end of the ochrea is always clearly swollen and forms an ant nest. A petiole may be present or absent. The rachis and the tendril are studded with backward-pointing thorns. The relatively few leaflets are simply folded, lanceolate or rhombic and torn at the front end. Their underside is often hairy white.

Inflorescences

The inflorescences are formed at the same time in the axils of the most distal, often reduced leaves. Usually they are branched one or two times. The inflorescence stalk is partially fused with the trunk. The cover sheet is two-keeled, tightly fitting and mostly hidden in the leaf sheath of the bract of the inflorescence. The inflorescence axis is much longer than the stalk. The bracts on the inflorescence axis are tubular, tightly fitting and hardly or not reinforced, but densely hairy. The bracts on the side axes of the first order are similar. The flower-bearing axes (rachillae) are mostly distant, cylindrical and cat-like . They carry a few empty basal bracts and a tight spiral of imbricate bracts that are laterally fused together. They are seldom distant, then each bract forms a pit. The flowers are single.

blossoms

The flowers are hermaphroditic, which is rare for palm trees. They are proterandrian . The calyx is tubular in the lower area and has three lobes. The crown is also tubular with three lobes. The six to nine stamens are at the mouth of the corolla tube. The gynoeceum is triple, rounded and covered with scales. The stylus is conical or pyramidal with three narrow grain lines. The ovules are basal and anatropic .

The pollen is spherical. The germ openings are either equatorial diporate or meridional zonasulcat. The longest axis measures 25 to 60 microns.

Fruits and seeds

The fruit is spherical to egg-shaped and contains a seed. The exocarp is covered with vertical rows of imbricate scales pointing backwards. The exocarp is thin, fleshy and sweet; an endocarp is not differentiated. The seed sits basal, the seed coat is thin, not fleshy. The endosperm is homogeneous or ruminate and has a noticeable pit.

ecology

Several species that have an inflated ochrea live in close association with ants . The ants keep aphids on young tissue inside the ochrea , old dry ochreas are used as a breeding chamber. In some species, such as Korthalsia robusta and Korthalsia hispida , the ants give alarm signals by hitting their mandibles on the dry ochrea. The meaning of the ant-rattan relationship has not been clearly clarified, but it is likely to lie in the defense of the plants against herbivores .

Bees have been observed on the flowers of Korthalsia laciniosa . The fruits of several species are eaten by hornbills of the species Anthracoceros convexus .

Distribution and locations

The genus occurs in Southeast Asia and Malesia . The main area of ​​distribution is in the perhumid areas of the Sunda Shelf. The total area extends in the north to Indochina , Burma and the Andamans , in the southeast to Celebes and New Guinea . The species are restricted to the lowland rainforests and the hills, but are absent in the mountain rainforest . They are common in primary forests, but are also well adapted to disturbances and are therefore also common in older secondary forests and in regenerated forests.

Some species have a very narrow ecological amplitude, for example Korthalsia concolor only occurs on ultra-basic rock in Sabah ( Borneo ).

Systematics

The genus Korthalsia flower is placed within the family Arecaceae in the subfamily Calamoideae , tribe Calameae . It alone forms the subtribe Korthalsiinae. The monophyly of the genus was not investigated (as of 2008). The relationship to the other subtribes is unclear.

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

use

Korthalsia forms very hard sticks that are processed locally into basketry. However, they are disfigured by the large knot scars and the attached leaf sheaths, so that the species do not play a role in the rattan trade.

literature

  • 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. 179-181.

Individual evidence

  1. ↑ Lotte Burkhardt: Directory of eponymous plant names . Extended Edition. Botanic Garden and Botanical Museum Berlin, Free University Berlin Berlin 2018. [1]
  2. ↑ a b Rafaël Govaerts (ed.): Korthalsia. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved August 2, 2018.

Web links

  • Korthalsia on the homepage of the Fairchild Tropical Botanic Garden