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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: studied by us.

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classifications. See also Guidelines for using data taken from Web publications.

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: 11th December 2017.’.