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The grass genera of the world

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

Chloachne Stapf

~ Poecilostachys

Habit, vegetative morphology. Perennial; rhizomatous, or stoloniferous. Culms 30–100 cm high; herbaceous; branched above. Culm nodes glabrous. Leaves not basally aggregated; non-auriculate. Sheath margins free. Leaf blades lanceolate; broad; slightly cordate, or not cordate, not sagittate; pseudopetiolate, or not pseudopetiolate; cross veined. Ligule a fringed membrane.

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant, or all alike in sexuality; hermaphrodite, or hermaphrodite and sterile (sometimes sterile at the base of the inflorescence).

Inflorescence. Inflorescence of spicate main branches (mostly), or paniculate (the branches sometimes themselves branched at the base); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets in triplets (or small clusters), or paired; secund (the racemes unilateral); pedicellate; not in distinct ‘long-and-short’ combinations.

Female-fertile spikelets. Spikelets 6–8 mm long; abaxial; compressed laterally; falling with the glumes. Rachilla prolonged beyond the uppermost female-fertile floret (the prolongation minute, vestigial), or terminated by a female-fertile floret; the rachilla extension when present, naked. Hairy callus absent.

Glumes two; very unequal; shorter than the adjacent lemmas, or long relative to the adjacent lemmas (i.e., the upper glumes); dorsiventral to the rachis; hairy (with very large, sparse hairs, or stiff, tubercle-based bristles); pointed (acuminate); awnless; non-carinate; similar (membranous-herbaceous). Lower glume 3–5 nerved. Upper glume 5 nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1; paleate. Palea of the proximal incomplete florets reduced. The proximal incomplete florets sterile. The proximal lemmas similar to the glumes, hairy or bristly; awnless; 7–8 nerved; decidedly exceeding the female-fertile lemmas; less firm than the female-fertile lemmas; not becoming indurated.

Female-fertile florets 1. Lemmas narrow; similar in texture to the glumes to decidedly firmer than the glumes (somewhat papyraceous); smooth (shining); not becoming indurated; entire; pointed; awnless to mucronate; hairless; glabrous (shiny); non-carinate; having the margins lying flat on the palea; with a clear germination flap; 5 nerved. Palea present; relatively long; entire (acute); awnless, without apical setae; textured like the lemma; not indurated; 2-nerved; 2-keeled (‘folded on the margins’). Lodicules present; 2; free; fleshy; glabrous; not or scarcely vascularized. Stamens 3. Ovary apically glabrous. Styles fused. Stigmas 2.

Fruit, embryo and seedling. Fruit small; compressed laterally (plano-convex). Hilum short. Embryo large; waisted.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Intercostal zones exhibiting many atypical long-cells to without typical long-cells. Mid-intercostal long-cells rectangular; having markedly sinuous walls (coarsely, deeply). Microhairs present; panicoid-type; (69–)81–83 microns long; (30–)48–51(–53) microns wide at the septum. Microhair total length/width at septum 12.8–16.9. Microhair apical cells 4.8–5.7 microns long. Microhair apical cell/total length ratio 0.43–0.74. Stomata common; about 33 microns long. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; not paired (apparently solitary); silicified. Intercostal silica bodies tall-and-narrow. Costal short-cells conspicuously in long rows. Costal silica bodies ‘panicoid-type’.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade ‘nodular’ in section to adaxially flat; with the ribs more or less constant in size. Midrib conspicuous; with one bundle only. Bulliforms not present in discrete, regular adaxial groups (bulliform-like cells constituting most of adaxial epidermis). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.

Classification. Watson & Dallwitz (1994): Panicoideae; Panicodae; Paniceae. Soreng et al. (2015): Panicoideae; Panicodae; Paniceae. 2 species.

Distribution, phytogeography, ecology. Tropical Africa.

Shade species.

References, etc. Leaf anatomical: this project.

Illustrations. • C. oplismenoides: Jacques-Félix, 1962. • C. oplismenoides, as C. secunda: Hook. Ic. Pl. 31 (1916)


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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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