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The grass genera of the world

L. Watson, T.D. Macfarlane, and M.J. Dallwitz

Coelachyropsis Bor

~ Coelachyrum

Type species: C. lagopoides (Burm. f.) Bor.

Habit, vegetative morphology. Annual; decumbent. Culms 10–25 cm high; herbaceous; amply branched above. Culm nodes glabrous. Leaves not basally aggregated; non-auriculate. Leaf blades narrow; 2–6 mm wide; exhibiting multicellular glands abaxially. The abaxial leaf blade glands on the blade margins, or costal (elongated, one cell file, with 4–8 cells). Leaf blades without cross venation; persistent. Ligule a fringed membrane.

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.

Inflorescence. Inflorescence of spicate main branches (2–3 short spikes, in the material seen); digitate. Primary inflorescence branches 2–3. Inflorescence with axes ending in spikelets. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary; secund; biseriate.

Female-fertile spikelets. Spikelets 5–7 mm long; compressed laterally; disarticulating above the glumes (?), or not disarticulating. Rachilla prolonged beyond the uppermost female-fertile floret; hairless; the rachilla extension with incomplete florets. Hairy callus absent.

Glumes two; more or less equal; shorter than the spikelets; shorter than the adjacent lemmas; lateral to the rachis; hairless; glabrous; pointed; awnless (but mucronate); carinate; similar (membranous-hyaline, broadly lanceolate acuminate). Lower glume 1 nerved. Upper glume 3–4 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped.

Female-fertile florets 5–8. Lemmas broadly ovate, acuminate; not saccate; similar in texture to the glumes (membranous); not becoming indurated; entire; pointed; mucronate (attenuate into the mucro); hairy (with long white hairs on the lower half along the nerves); carinate; having the margins lying flat on the palea; without a germination flap; 3 nerved. Palea present; relatively long; entire; awnless, without apical setae; not indurated (membranous); 2-nerved (with hairs along their lower two thirds); 2-keeled. Lodicules present; 2; free; fleshy; not or scarcely vascularized. Stamens 3 (with tiny anthers). Anthers not penicillate; without an apically prolonged connective. Ovary apically glabrous. Styles free to their bases. Stigmas 2.

Fruit, embryo and seedling. Fruit free from both lemma and palea; small (about 1 mm long); compressed dorsiventrally (angular when dry, and concave on the side away from the embryo); sculptured (cf. Acrachne). Hilum short. Pericarp free. Embryo large. Endosperm hard.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present; intercostal. Intercostal papillae over-arching the stomata, or not over-arching the stomata; consisting of one oblique swelling per cell (large). Long-cells markedly different in shape costally and intercostally (the costals conventional, with sinuous walls). Intercostal zones with typical long-cells (long-cells thin walled, deforming, some may be short). Mid-intercostal long-cells having straight or only gently undulating walls. Microhairs present; more or less spherical; clearly two-celled; chloridoid-type. Microhair apical cell wall of similar thickness/rigidity to that of the basal cell. Microhair basal cells 9–12 microns long. Microhair total length/width at septum about 2. Microhair apical cell/total length ratio about 0.5. Stomata common. Subsidiaries non-papillate; including both triangular and parallel-sided forms on the same leaf. Guard-cells overlapping to flush with the interstomatals (except for overlapping by papillae). Intercostal short-cells absent or very rare. Costal short-cells conspicuously in long rows (although the short-cells are often rather long). Costal silica bodies present in alternate cell files of the costal zones; ‘panicoid-type’; cross shaped and nodular (with points); sharp-pointed (the crosses and dumb-bells with points).

Transverse section of leaf blade, physiology. Lamina mid-zone in transverse section open.

C4; XyMS+. PCR sheaths of the primary vascular bundles interrupted; interrupted both abaxially and adaxially. PCR sheath extensions absent. Leaf blade probably adaxially flat. Midrib not readily distinguishable; with one bundle only; with colourless mesophyll adaxially (there being colourless tissue adaxial to all the large vascular bundles). Bulliforms present in discrete, regular adaxial groups; in simple fans and associated with colourless mesophyll cells to form deeply-penetrating fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders absent (colourless, large-celled bundle sheath extensions adaxially). Sclerenchyma all associated with vascular bundles. The lamina margins with fibres.

Classification. Watson & Dallwitz (1994): Chloridoideae; main chloridoid assemblage. Soreng et al. (2015): Chloridoideae; Cynodonteae; Eleusininae. 1 species (C. lagopoides).

Distribution, phytogeography, ecology. Southern India, Ceylon.

References, etc. Leaf anatomical: this project.


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Cite this publication as: ‘Watson, L., Macfarlane, T.D., and Dallwitz, M.J. 1992 onwards. The grass genera of the world: descriptions, illustrations, identification, and information retrieval; including synonyms, morphology, anatomy, physiology, phytochemistry, cytology, classification, pathogens, world and local distribution, and references. Version: 13th November 2017. delta-intkey.com/grass’.

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