The grass genera of the world
Habit, vegetative morphology. Annual. Culms 15–60 cm high; herbaceous; unbranched above (branching near the base). Leaves not basally aggregated; without auricular setae. Leaf blades lanceolate; broad; sagittate; flat; pseudopetiolate (except the uppermost); rolled in bud, or once-folded in bud (? - supposedly not pleated). Ligule a fringed membrane (usually), or an unfringed membrane (rarely).
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence of spicate main branches; open; non-digitate. Inflorescence with axes ending in spikelets, or axes not ending in spikelets (depending on interpretation of the bristle). Inflorescence espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets subtended by solitary bristles (each subtended by a bristle). The bristles persisting on the axis. Spikelets solitary; secund; pedicellate. Pedicel apices discoid.
Female-fertile spikelets. Spikelets abaxial; compressed dorsiventrally; falling with the glumes. Rachilla terminated by a female-fertile floret. Hairy callus absent.
Glumes two; relatively large; very unequal; shorter than the adjacent lemmas; dorsiventral to the rachis; hairless; awnless (G2 apiculate); non-carinate; very dissimilar. Lower glume 3 nerved. Upper glume 5–7 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 fully developed. The proximal incomplete florets male. The proximal lemmas awnless; not becoming indurated (textured like the G2).
Female-fertile florets 1. Lemmas cymbiform; decidedly firmer than the glumes; rugose; becoming indurated (crustaceous); entire; pointed, or blunt; awnless (but sub-apiculate); hairless; carinate; having the margins inrolled against the palea; with a clear germination flap; 3 nerved. Palea present; relatively long; entire; awnless, without apical setae (glabrous); textured like the lemma (crustaceous); indurated; 2-nerved; keel-less (flat backed). Lodicules present; free; fleshy; glabrous; not or scarcely vascularized. Stamens 3. Anthers not penicillate; without an apically prolonged connective. Ovary apically glabrous. Stigmas 2.
Fruit, embryo and seedling. Fruit small (1.25 mm long); compressed dorsiventrally (ventrally concave). Hilum short. Embryo large.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally (the intercostals much broader). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type. Stomata common. Subsidiaries low to high dome-shaped and triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells absent or very rare. Costal short-cells conspicuously in long rows. Costal silica bodies panicoid-type; dumb-bell shaped and nodular.
Transverse section of leaf blade, physiology. C4; XyMS. PCR cell chloroplasts centrifugal/peripheral. Leaf blade nodular in section to adaxially flat. Midrib conspicuous (with a large abaxial keel); having a conventional arc of bundles (including 3 major bundles); with colourless mesophyll adaxially. Bulliforms not present in discrete, regular adaxial groups (seemingly, in the poor material seen). Many of the smallest vascular bundles unaccompanied by sclerenchyma. Combined sclerenchyma girders present (with the major bundles). Sclerenchyma all associated with vascular bundles.
Classification. Watson & Dallwitz (1994): Panicoideae; Panicodae; Paniceae. Soreng et al. (2015): Panicoideae; Panicodae; Paniceae; Cenchrinae. 1 species.
Distribution, phytogeography, ecology. Africa.
Mesophytic; shade species; glycophytic.
References, etc. Morphological/taxonomic: Schweickerdt 1936. Leaf anatomical: this project.
Illustrations. • C. sagittifolia, abaxial epidermis of leaf blade: this project
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: 13th November 2017. delta-intkey.com/grass’.