Nicobariodendron sleumeri
| Nicobariodendron sleumeri | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Nicobariodendron | ||||||||||||
| Vasudeva Rao & Chakrab. | ||||||||||||
| Scientific name of the species | ||||||||||||
| Nicobariodendron sleumeri | ||||||||||||
| Vasudeva Rao & Chakrab. | ||||||||||||
Nicobariodendron sleumeri is the only species of the Nicobariodendron plant genus . The tree is on to India belonging Nicobar home. It has been little researched, and its systematic positioning within the Bedecktsamer is unclear.
description
Appearance and leaf
Nicobariodendron sleumeri is a tree that reaches heights of growth of 8 to 35 meters. The 1 to 6 mm thick, stem-round branches have a bare, greyish, brownish or blackish bark, which is covered with whitish lenticels . The alternate leaves are arranged in two rows and are divided into a petiole and a leaf blade. The petiole is 3 to 8 mm long and 1 to 2 mm thick. The shape of the undivided leaf blade is oblong-elliptical to obverse-elliptical; they are 5.5 to 10 cm long, 2 to 4 cm wide and have entire margins. The base of the spreader is narrowed, the rounded tip of the spreader has a suddenly separated, 5 to 12 mm long, blunt trickle tip . They have a leathery structure and a bare, shiny surface. When dry, they are dark reddish brown, brown or blackish on the upper side, brown and dotted on the underside, with pinnate-shaped veins . The midrib is flat on the upper side of the leaf or, as always on the underside, slightly protruding. The five to nine pairs of side veins are thin and more clearly visible on the underside than on the top; they are bent towards the edge of the sheet and network. Between the side veins, smaller veins that are more distinct on the bottom form a network. Stipules are missing.
Inflorescence and flower
Nicobariodendron sleumeri is dioeciously segregated ( diocesan ). The male inflorescences are axillary, usually solitary, rarely two or three standing, usually simple, rarely by a composite or two branches at the base grape . The grape axis is thin, 4 to 11 cm long, 0.8 to 1.2 mm thick at the base, longitudinally striated and sparsely short whitish -stiff-haired . The bracts are sub-like or often triangular or ovate, 1 to 2 mm long, 0.5 to 1 mm wide, glabrous on the surface or sometimes sparsely short whitish-stiff-haired, on the edge with whitish eyelashes. The flower stalks are 1.2 to 2 mm long, 0.2 to 0.3 mm thick and glabrous.
The fragrant male flowers are about 2 mm in diameter. The calyx is four to five-fold, about 2 mm long and glabrous, the overlapping calyx lobes are oblong to ovoid or often triangular-ovoid, 1 to 1.5 mm long, 0.6 to 1.2 mm wide and blunt. The four to five free, overlapping, yellowish petals sit on the edge of the disc in front of the gaps between the calyx tips; they are usually elongated, sometimes ovate, 1.2 to 1.5 mm long, 0.7 to 1 mm wide, blunt and glabrous. The ring-shaped disc, which lies within the stamen circle, is concave, slightly fleshy and covered with short whitish downy hairs. The two stamens are free, sit next to each other at the base of the petals and protrude above the crown. The stamens are 1.5 to 2.5 mm long, thin, but broadened at the base. The anthers are attached to the stamens with their backs, consist of two counters and tear open lengthways. They are circular and 0.5 to 0.7 mm in diameter. The rudimentary pistil ( Pistillodium ) is sunk somewhat into the disc; it is small and has a thread-like stylus .
The female flowers are unknown. The axillary fruit stands are 6 to 10 cm long and simple or often compound grapes with one or two branches at the base. The fruiting axis is longitudinally striated, 1 to 2 mm thick at the base and sparsely covered with short, whitish, stiff hair. The single-fan drupes are elongated-ellipsoidal or narrowly obovate, 17 to 20 mm long, about 10 mm thick, contracted at the base, rounded or flattened at the tip. They are bare, thin-walled, brown and have a slightly grooved surface. The fruit stalk is about 3 mm long, 0.8 to 1 mm thick. The five fruit calyx leaves are elongated, 1.5 to 2 mm long, 0.8 to 1 mm wide and blunt. The disc is flattened, slightly fleshy and covered with short whitish downy hairs. The only seed is attached to the base of the cavity of the fruit.
Nicobariodendron sleumeri flowers in October and fruit in December.
Distribution and systematics
Nicobariodendron sleumeri is endemic to the Nicobar Islands and so far known from the islands of Great Nicobar and Katchal , which are about 80 kilometers apart . There the species occurs in inland forests at altitudes of up to 100 meters.
Nicobariodendron sleumeri was described in 1986 on the basis of two herbarium specimens : one came from a male tree on Groß Nikobar, the other from a female tree on Katchal. Since then, no further research results have become known. Details of the female flowers, especially the structure of the ovaries and ovules, as well as the seeds, the bark and the stem, remain unknown. In the first description and in most of the subsequent publications, this tree is provisionally placed in the spindle tree family (Celastraceae). Because of the peculiar combination of characteristics and the lack of data on the ovary , the anatomy of wood and the molecular characteristics, this family assignment remains uncertain. In APG III , no allocation was made at the organizational level.
The specific epithet sleumeri honors the German-Dutch botanist Hermann Sleumer (1906–1993), who was involved in its research.
proof
- ↑ a b c d e f g h i M. K. Vasudeva Rao, T. Chakrabarty: Nicobariodendron Vasud. & T.Chakrab. (Celastraceae): a new genus from the Nicobar Islands, India. In: Journal of Economic and Taxonomic Botany. Volume 7, No. 3, 1985 (publ. 1986), pp. 513-516.
- ↑ a b c Mark P. Simmons: Celastraceae In: Klaus Kubitzki (Ed.): The Families and Genera of Vascular Plants . Volume 6: Flowering Plants, Dicotyledons: Celastrales, Oxalidales, Rosales, Cornales, Ericales . Springer, Berlin / Heidelberg / New York 2004, ISBN 3-540-06512-1 , pp. 61 (English, limited preview in Google Book Search).
- ↑ Distance measurement in Google Earth , accessed on October 28, 2010.
- ↑ the publication dates from 1985, but was not delivered until the following year ( Kew Record of Taxonomic Literature , accessed on January 30, 2010).
- ↑ Li-Bing Zhang, Mark P. Simmons: Phylogeny and Delimitation of the Celastrales Inferred from Nuclear and Plastid Genes. In: Systematic Botany. Volume 31, No. 1, 2006, pp. 122-137, doi : 10.1600 / 036364406775971778 .
- ↑ Angiosperm Phylogeny Group: An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III. In: Botanical Journal of the Linnean Society. Volume 161, No. 2, 2009, pp. 105-121, doi : 10.1111 / j.1095-8339.2009.00996.x .