Wallichia

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Wallichia
Wallichia oblongifolia

Wallichia oblongifolia

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

Wallichia is a genus of palm native to Southeast Asia. The genus was named after the Danish doctor and botanist Nathaniel Wallich (1786-1854). He was an employee of the East India Company and later became superintendent of the company's garden in Calcutta .

Wallichia disticha
Wallichia oblongifolia

features

The representatives are dwarf to medium-sized palms with pinnate leaves. They are single or multi-stemmed and bloom only once ( hapaxanthia ). They are predominantly single sexed ( monoecious ), diocyte in the genus is questionable. The palms are trunkless, bush-shaped or tree-shaped. The trunk has contracted or elongated internodes . These are covered by the persistent, fibrous leaf bases and leaf sheaths .

The chromosome number is 2n = 32.

leaves

The leaves are arranged in a spiral or two lines, pinnate unpaired and induplicate. The leaf sheath often extends beyond the petiole and thus forms a ligule. Over time, it breaks down into black fibers. The petiole is well developed. The leaflets are simply folded and linear-lanceolate. They are irregularly rhombic or deeply lobed, sometimes also with ears at the base. The upper side of the leaf is bare, the underside densely covered with hair and scales.

Inflorescences

The inflorescences are between the leaves (interfoliär) and always individually. They break through the leaf sheaths and arise in a basipetal sequence. They are only branched once, unisexual and mostly different: the female are the distal or "terminal" ones, the male the proximal ones, which are often hidden by conspicuous bracts.

The peduncle is usually hairy and scaly brown. The cover sheet is small, two-keeled and only roehrig at the base. There are several bracts on the peduncle, which are arranged in a spiral and are much larger than the previous leaf. They are tubular at the base, tear open and are usually thickly covered with brown scales and hair.

The inflorescence axis is usually longer than the inflorescence stalk. The bracts are very small. The axis carries numerous flower-bearing side axes (rachillae), which are rather slender and densely hairy. They have small bracts in a spiral arrangement with the flowers in their axils.

blossoms

The male flowers are in pairs or individually. Sometimes they are accompanied by a rudiment of a female flower. The calyx is tubular with three lobes or teeth. The receptaculum is elongated and stem-like between the calyx and crown . The crown clearly towers above the chalice. It is tubular at the base and has three long tips. There are 3 to 15 stamens present. The stamens are connected at the base to form a short to long column. In addition, they are partially or completely fused with the corolla tube, sometimes with part of the tip. The anthers are straight. One stamp rudiment is missing. The pollen is ellipsoidal and bisymmetrical. The germ opening is a distal sulcus. The longest axis measures 24 to 27 µm.

The female inflorescences are mostly upright and carry fewer, but more powerful rachillae. The flowers are individually arranged in a spiral. Each stands in the axilla of a bract and is surrounded by three bracteoles. The three sepals are low, rounded and imbricat . They are free or at most grown together in the lowest area. The three petals are fused to about half, the free parts are valvate . There are 0 to 3 staminodes . The ovary is spherical and two to dreifächrig with one ovule per subject. The scar is apical and conical. The ovules are hemianatropic .

Fruits and seeds

The fruit is ellipsoidal, small and reddish or purple in color. It contains one or two, rarely three seeds. The scar remains are apical. The exocarp is smooth, the mesocarp is fleshy and covered with needle-shaped, irritating crystals. An endocarp is not differentiated. The seeds are basal. They are ellipsoidal or hemispherical. The endosperm is homogeneous. The embryo sits on the side.

Distribution and locations

The representatives come from the Nepalese Himalayas and Upper Burma to China and south to the Thai peninsula. They grow in the humid tropical forests from sea level up to 2000 m above sea level. The genus becomes rarer towards the south, indicating an adaptation to cooler and more seasonal climates. Most of the species are types of understory. Only Wallichia disticha is a medium-sized tree that occurs in groups on the steep sandstone slopes of Eastern Sikkim .

Systematics

The genus Wallichia Roxb. is placed within the family Arecaceae in the subfamily Coryphoideae , tribe Caryoteae . The genus is likely monophyletic . Her sister group is Arenga . Type species is Wallichia caryotoides Roxb.

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

use

Wallichia oblongifolia leaves were used to cover roofs in the past. From the tribe of Wallichia disticha was Sago won.

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. 304-306.

Individual evidence

  1. ↑ a b c d e f g h i Rafaël Govaerts (Ed.): Wallichia. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved August 4, 2018.

Web links

Commons : Wallichia  - collection of images, videos and audio files
  • Wallichia on the homepage of the Fairchild Tropical Botanic Garden