The grass genera of the world
Including Sclerochlaena A. Camus
Habit, vegetative morphology. Perennial. Culms 20–30 cm high; herbaceous; branched above. Culm nodes hidden by leaf sheaths. Culm leaves present. Leaves not basally aggregated; non-auriculate. Leaf blades lanceolate to ovate-lanceolate; rather flimsy; relatively broad; 5–10 mm wide; flat; without cross venation; persistent. Ligule a fringed membrane. Contra-ligule absent.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets (in the material seen). The spikelets of sexually distinct forms on the same plant; hermaphrodite and male-only, or hermaphrodite and sterile (this in the material seen). The male and female-fertile spikelets mixed in the inflorescence. The spikelets more or less overtly heteromorphic.
Inflorescence. Inflorescence of spicate main branches (a raceme of short, spicate branches). Inflorescence with axes ending in spikelets. Rachides narrowly winged. Inflorescence espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes short racemes. The racemes spikelet bearing to the base. Spikelet-bearing axes solitary; with substantial rachides; persistent. Spikelets paired; secund (the raccemes unilateral); biseriate (the pairs in two ranks); pedicellate, or subsessile and pedicellate (the pedicels winged, with long, stiff, cushion based hairs). Pedicel apices discoid to cupuliform. Spikelets imbricate; consistently in long-and-short combinations; unequally pedicellate in each combination. Pedicels of the pedicellate spikelets free of the rachis. The shorter spikelets male-only, or sterile. The longer spikelets hermaphrodite, or female-only.
Female-sterile spikelets. The short-pedicelled spikelets sterile or male, with a long-awned lower glume, membranous upper glume and membranous lower lemma. Rachilla of male spikelets terminated by a male floret. The male spikelets with glumes (these awned); without proximal incomplete florets; 2 floreted. The lemmas awned (the lower). Male florets 2; 3 staminate.
Female-fertile spikelets. Spikelets 1.5 mm long; abaxial; strongly compressed laterally; falling with the glumes; not disarticulating between the florets; with conventional internode spacings. Rachilla terminated by a female-fertile floret. Callus absent.
Glumes two; more or less equal (discounting awns); about equalling the spikelets to exceeding the spikelets; long relative to the adjacent lemmas; dorsiventral to the rachis; hairless; glabrous; (the lower long) awned (the awn more or less deciduous); carinate; very dissimilar (the lower narrower, membranous, with a long, slender antrorsely scabrous awn from a slight sinus, the upper larger, saccate, hooded at the tip, awnless, leathery). Lower glume thinly 3 nerved. Upper glume distinctly saccate; thinly 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 (the palea saccate above). Palea of the proximal incomplete florets fully developed. The proximal incomplete florets male. The proximal lemmas saccate, hooded at the tip; awnless; 3 nerved; decidedly exceeding the female-fertile lemmas; decidedly firmer than the female-fertile lemmas (becoming cartilaginous).
Female-fertile florets 1. Lemmas less firm than the glumes (hyaline); not becoming indurated; entire; awnless; hairless; glabrous; non-carinate; having the margins lying flat on the palea; without a germination flap; 3 nerved. Palea present; relatively long; tightly clasped by the lemma; entire; awnless, without apical setae; textured like the lemma; not indurated; nerveless; keel-less. Palea back glabrous. Lodicules present; 2; free; fleshy; glabrous; not or scarcely vascularized. Stamens 3. Ovary apically glabrous. Styles free to their bases; free. Style bases adjacent. Stigmas 2.
Fruit, embryo and seedling. Fruit compressed laterally.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally (the costals much narrower and more regularly rectangular). Intercostal zones with typical long-cells to exhibiting many atypical long-cells (these generally rather short, some very short). Mid-intercostal long-cells more or less isodiametric or irregular to rectangular; having markedly sinuous walls (coarsely sinuous). Microhairs present; elongated; clearly two-celled; panicoid-type. Stomata common (confined to rows alongside the costae). Subsidiaries non-papillate; dome-shaped and triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells absent or very rare. With long, slender, cushion-based macrohairs intercostally. Costal short-cells conspicuously in long rows. Costal silica bodies present and well developed; panicoid-type; cross shaped, dumb-bell shaped, and nodular.
Transverse section of leaf blade, physiology. C3 (delta value: W.V. Brown 1977); XyMS+. Mesophyll without circular cells; not traversed by colourless columns; without arm cells; without fusoids.
Classification. Watson & Dallwitz (1994): Panicoideae; Panicodae; Paniceae (Boivinelleae). Soreng et al. (2015): Panicoideae; Panicodae; Paniceae; Boivinellinae. 2 species.
Distribution, phytogeography, ecology. Madagascar.
In damp places.
References, etc. Morphological/taxonomic: Bosser 1965. Leaf anatomical: studied bu us - C. madagascariensis Hack.
Special comments. Fruit data wanting. Illustrations. • Inflorescence detail (C. madagascariensis). Cyphochlaena madagascariensis. Spikelets paired, sterile and hermaphrodite, both forms with long-awned lower glumes. • Inflorescence detail (C. madagascariensis)
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. delta-intkey.com/grass’.