Eleocharis R.Br. (Brown 1810: 224)

Rasaminirina, Fitiavana & Larridon, Isabel, 2023, The genera of Cyperaceae of Madagascar, Plant Ecology and Evolution 156 (3), pp. 276-310 : 276

Eleocharis R.Br. (Brown 1810: 224)

Websteria S.H.Wright ( Wright 1887: 135)

Type species.

Scirpus palustris L. [= Eleocharis palustris (L.) Roem. & Schult.]

Description of the genus.

Very small to medium-sized tufted annuals or large rhizomatous, stoloniferous perennials; rhizome often strong, horizontal, often producing stolons. Culms scapose, 3-4 angular, ridged or terete, occasionally septate, ancipitous or bulbously thickened at base. Leaves reduced to inconspicuous basal sheaths, rarely with a short blade, eligulate. Primary bracts absent, rarely proximal scale of spikelet resembling short bract. Inflorescence solitary terminal spikelet, usually quite short and ebracteate. Spikelets with 2-many spirally arranged, rarely subdistichous, deciduous imbricate glumes, each subtending a floret. Lowermost glume often empty or with a vegetative bud, rarely flower-bearing. Floret bisexual. Bristles barbellate, (0-)3-6(-10), or reduced to a narrow rim underlying nutlet, shorter or longer than nutlet and shed with it. Stamens 1-3; anthers linear. Style 2-3-fid, upper portion deciduous, base enlarged persistent as a conical or flattened appendage on nutlet. Nutlets obovoid, lenticular or trigonous, beaked smooth or variously ornamented with pits in longitudinal rows.

Distribution and ecology.

Eleocharis is a cosmopolitan genus ( POWO 2022). It grows in forest, wet grasslands, freshwater wetlands, along rivers, lake margins, and rice fields, and in rocky areas. Eleocharis occurs throughout Madagascar; 12 species are known including e.g. Eleocharis acutangula (Roxb.) Schult. (Fig. 4C ) and Eleocharis dulcis (Burm.f.) Trin. ex Hensch. (Fig. 13 ).

Figures

Figure 4. A. Coleochloa setifera. B. Costularia itremoensis. C. Eleocharis acutangula. All photos taken in the Itremo Massif Protected Area by Fitiavana Rasaminirina.

Figure 13. Eleocharis dulcis. A. Habit (x 1 / 3). B. Inflorescence (x 1.5). C. Floret (x 10). D. Nutlet (x 12). A from Kirika et al. NMK 778; B from Vesey-Filtzgerald 401; C from Milne-Redhead & Taylor 9164; D from Faden et al. 96 / 468. Drawn by Juliet Beentje, reproduced with permission from the artist, originally published in Hoenselaar et al. (2010).