Diplacrum R.Br. (Brown 1810: 241)

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

Diplacrum R.Br. (Brown 1810: 241)

Type species.

Diplacrum caricinum R.Br.

Description of the genus.

Small to medium-sized annuals or tufted, rarely stoloniferous perennials. Culms scapose or leafy, often short. Leaves eligulate; blade linear or lanceolate, alternate, simple, often reddish purple abaxially. Primary bracts leaf-like, sheathing. Inflorescence paniculate or capitate; partial inflorescences anthelate or capitately contracted. Spikelets many, lateral spikelets usually male, terminal spikelets usually female. Glumes male spikelets with few distichous, persistent glumes, each subtending a male floret; female spikelet with 2 distichous, persistent glumes, sometimes deciduous with the fruit, surrounding a pseudo-terminal female floret. Florets unisexual. Bristles absent. Stamens 1; anthers sightly oblongs. Pistil seated on a basal trilobed disc, lobes opposite the 3 main ribs; style 3-fid; base not distinct, not thickened, deciduous. Nutlets subglobose to ovoid, inconspicuously 3-ribbed, beak short, surface smooth, ribbed, or reticulate.

Distribution and ecology.

Diplacrum is widely distributed in the tropics and tubtropics ( POWO 2022). It grows in damp soils and freshwater wetlands including rice fields, usually near sea level. A single species of Diplacrum , i.e. Diplacrum africanum (Benth.) C.B.Clarke (Fig. 6 ), is known from northwestern and east central Madagascar, and from the southeast along the mountain range.

Figures

Figure 6. Diplacrum africanum. A, C. Habit. B Leaf. D. Inflorescence. E. Spikelets, male and female with bract and prophyll. F. Prophyll. G - H. Female spikelet, with and without nutlet. I - J. Nutlet, lateral and basal view. B-D, G-J from Robinson 2851; A, E, F from Bidgood et al. 3967. Scale bars: A, B = 25 mm; C = 10 mm; D-H = 1 mm; I, J = 0.5 mm. Drawn by Jane Browning, reproduced with permission from the artist, originally published in Browning et al. (2020).