Coleochloa Gilly (Gilly 1943: 12)

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

Coleochloa Gilly (Gilly 1943: 12)

Type species.

Coleochloa abyssinica (Hochst. ex A.Rich.) Gilly

Description of the genus.

Tufted or cushion-forming perennials; rhizomes extensively branched, infrequently forming a small caudex. Culms scapose or nearly so, compressed below, sometimes subcylindrical; erect or slightly wanting, basal part of culms covered by remains of old leaf sheaths. Leaves basal only, distichous; leaf sheath open on ventral side; ligule a line of fine hairs; contraligule not developed; blade flat or inrolled, deciduous. Involucral bracts more or less leaf-like; sheaths partly closed. Inflorescence terminal, paniculate, with few to many spikelet-like spikes; spikes bisexual, with numerous lateral spikelets subtended by small, densely spirally arranged glume-like bracts. Spikelet unisexual (male) or bisexual; lateral spikelets with an irregularly shaped prophyll. Glumes distichous, persistent, the larger 1-2 each subtending a flower, enclosed by the wings of the next glume. Basal spikelets with 1-2 male florets, apical spikelets mostly with 1 male and 1 female floret, more rarely completely female. Perianth surrounding the style base by 3 small, long fimbriate hypogynous scales, deciduous with the fruit. Stamens 2-3. Style 3-fid; base not distinct, tapering, persistent. Nutlets fusiform, trigonous, long beaked, surface smooth.

Distribution and ecology.

Coleochloa occurs in tropical and southern Africa and Madagascar ( POWO 2022). It grows on inselbergs, between 600 to 2000 m in elevation. A single species of the genus, i.e. Coleochloa setifera (Ridl.) Gilly (Figs 3 , 4A ), occurs in northern and southeastern Madagascar and in the Central Highlands.

Figures

Figure 3. Coleochloa setifera. A. Habit, entire plant. B. Habit. C. Part of culm and leaf sheath. D. Leaf sheath opened to show ligule. E. Nutlet split open, seed enclosed. F. Seed. G. Nutlet, some bristles removed. H. Bristles detached from base of nutlet. I. Three fascicles of spikelets. J. Mature anther. K. Spikelet and bract, abaxial view. L. Spikelet, bract removed, adaxial view. M. Spikelet, glumes displaced, adaxial view. A-D, I-L from Browning 560; E-H from Pawek 13626 a. Scale bars: A = 250 mm; B = 40 mm; C-M = 1 mm. Drawn by Jane Browning, reproduced with permission from the artist, originally published in Browning et al. (2020).

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