Chloachne Stapf
Sometimes referred to 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; a fringed membrane.
Reproductive organization. Plants bisexual, 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 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.
Taxonomy. Panicoideae; Panicodae; Paniceae.
Distribution, ecology, phytogeography. 2 species; tropical Africa. Shade species.
Paleotropical. African. Sudano-Angolan and West African Rainforest. Somalo-Ethiopian and South Tropical African.
References, etc. Leaf anatomical: this project.
Cite this publication as: Watson, L., and Dallwitz, M. J. (1992 onwards). ‘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.’ http://biodiversity.uno.edu/delta/. Version: 18th August 1999. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1998), and Watson and Dallwitz (1994), and Watson, Dallwitz, and Johnston (1986) should also be cited (see References).