Eleocharis

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Eleocharis

Description

Annual or perennial herbs, in the latter case often stoloniferous. Leaves reduced to bladeless tubular sheaths often bearing a short erect mucro (vestige of the blade) at the apex. Inflorescence a terminal, ebracteate, single spikelet, sometimes proliferous. Flowers hermaphrodite. Stamens 1-3;

Distribution

Asia-Tropical: New World: present from the tropics to the polar regions of both hemispheres: present
According to SVENSON C. 150 spp., from the tropics to the polar regions of both hemispheres with the greatest concentration in the New World, in Malesia 19 spp.

Uses

Only a few species are of economic value. Some are used for matting (E. ochrostachys, E. dulcis). The tubers of E. dulcis are edible and the species is therefore cultivated.

Notes

Eleocharis is a natural genus nearest to Scirpus, Fimbristylis, and Bulbostylis; it is mainly characterized by the dilated style-base articulated with the ovary and persistent on the fruit, and the bladeless leaf-sheaths. The embryo, a variant of the Fimbristylis-type, is characterized by the first leaf more or less protruding from the germination-pore (). Only the members of ser. Pauciflorae (represented in Malesia by E. parvula) cause some difficulty as to the delimitation of the genus. Many authors consider them to belong to Scirpus. Their style-base, though confluent with the nut, is clearly different in texture and colour; therefore their natural place is obviously in Eleocharis; the type species of the series (see p. 537) has a typical Eleocharis embryo. , divided the genus into Eleocharis s.s. with eucyperoid anatomical structure, and Chlorocharis with chlorocyperoid anatomy.
Both Scirpus and Fimbristylis lack the persistent style-base of Eleocharis and Bulbostylis. The leaf-sheaths of Eleocharis are at most mucronate, but in Scirpus a comparatively well developed blade is usually present. In Fimbristylis and Bulbostylis the perianth is always lacking; in the former the style, falling off as a whole, leaves no button on the nut.
The etymologically more correct spelling 'Heleocharis' of LESTIBOUDOIS was followed by many authors. In the present revision the two spellings have not been considered as different in citing synonymy.
In general SVENSON'S arrangement, somewhat modified by S. T. BLAKE, has been followed; however, the circumscription of several species has been broadened.

Citation

KUNTH - in En. 1837: 139
SVENS. - in Rhodora. 1929
R. BR. - in Rhodora. 1932
CLARKE - in Kew Bull. 1908: 105
R. BR. - in Rhodora. 1937
KOYAMA - in J. Fac. Sc. Un. Tokyo. 1961
BOECK. - in Linnaea. 1869-1870: 418
R. BR. - in Rhodora. 1934
S.T.BLAKE - in Proc.R.Soc.Queensl. 1939
R. BR. - in Rhodora. 1939
STEUD. - in Syn. 1855: 75