The grass genera of the world
Including Filipedium Raiz. & Jain
Habit, vegetative morphology. Annual, or perennial; caespitose to decumbent. Culms herbaceous; branched above, or unbranched above. The branching simple (usually), or suffrutescent (e.g., in C. assimile). Culm nodes hairy, or glabrous. Culm internodes solid. The shoots aromatic, or not aromatic. Leaves not basally aggregated; non-auriculate. Leaf blades narrow; flat; without cross venation; persistent; rolled in bud. Ligule an unfringed membrane to a fringed membrane. Contra-ligule absent.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; hermaphrodite and male-only, or hermaphrodite and sterile; overtly heteromorphic (the pedicelled spikelets awnless); all in heterogamous combinations. Apomictic, or reproducing sexually.
Inflorescence. Inflorescence paniculate; open; with capillary branchlets; espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes very much reduced, or racemes; the spikelet-bearing axes with only one spikelet-bearing article to with 610 spikelet-bearing articles (racemes 1–2(-8) jointed); with very slender rachides (the internodes and pedicels with a translucent median furrow); disarticulating (C. parviflorum may have only one triplet per raceme, the triplet being shed as a unit); falling entire (C. parviflorum), or disarticulating at the joints. The pedicels and rachis internodes with a longitudinal, translucent furrow. Articles linear; without a basal callus-knob; densely long-hairy, or somewhat hairy, or glabrous. Spikelets in triplets (C. parviflorum), or paired; secund (pedicellate spikelets on one side of rachis, sessile ones on the other), or not secund (C. parviflorum); sessile and pedicellate; consistently in long-and-short combinations; in pedicellate/sessile combinations. Pedicels of the pedicellate spikelets free of the rachis. The shorter spikelets hermaphrodite. The longer spikelets male-only, or sterile.
Female-sterile spikelets. The male spikelets with glumes. The lemmas awnless.
Female-fertile spikelets. Spikelets compressed dorsiventrally; falling with the glumes. Rachilla terminated by a female-fertile floret. Hairy callus present.
Glumes two; more or less equal; long relative to the adjacent lemmas; awnless; very dissimilar. Lower glume two-keeled; convex on the back to concave on the back; not pitted; relatively smooth; 6–11 nerved. Upper glume 3 nerved (naviculate). Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. The proximal incomplete florets 1; sterile. The proximal lemmas awnless; 0 nerved; similar in texture to the female-fertile lemmas.
Female-fertile florets 1. Lemmas reduced to a hyaline stipe; less firm than the glumes; not becoming indurated; entire; awned. Awns 1; median; apical; geniculate; hairless (glabrous). Lemmas hairless; non-carinate; 1 nerved. Palea absent. Lodicules present; free; fleshy; glabrous. Stamens 3. Anthers not penicillate. Ovary apically glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small; compressed dorsiventrally. Hilum short. Embryo large. Endosperm containing only simple starch grains. Embryo without an epiblast; with a scutellar tail; with an elongated mesocotyl internode. Embryonic leaf margins overlapping.
Seedling with a long mesocotyl. First seedling leaf with a well-developed lamina. The lamina broad; supine; 13–20 veined.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present; costal and intercostal. Intercostal papillae over-arching the stomata; consisting of one oblique swelling per cell (intercostally), or several per cell (costally). Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally (fairly thin walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type. Stomata common, or absent or very rare. Subsidiaries non-papillate; triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs, or not paired (solitary); not silicified (usually). Costal short-cells conspicuously in long rows. Costal silica bodies panicoid-type.
Transverse section of leaf blade, physiology. C4; XyMS. Mesophyll with radiate chlorenchyma; traversed by columns of colourless mesophyll cells. Leaf blade adaxially flat. Midrib conspicuous; having a conventional arc of bundles; with colourless mesophyll adaxially. Bulliforms present in discrete, regular adaxial groups (in the furrows); in simple fans and associated with colourless mesophyll cells to form deeply-penetrating fans; associating with colourless mesophyll cells to form arches over small vascular bundles. Many of the smallest vascular bundles unaccompanied by sclerenchyma. Combined sclerenchyma girders present; forming figures. Sclerenchyma all associated with vascular bundles.
Phytochemistry. Leaves without flavonoid sulphates (1 species).
Cytology. Chromosome base number, x = 10. 2n = 20, 40, and 60. 2, 4, and 6 ploid.
Classification. Watson & Dallwitz (1994): Panicoideae; Andropogonodae; Andropogoneae; Andropogoninae. Soreng et al. (2015): Panicoideae; Andropogonodae; Andropogoneae; Anthistiriinae. 14 species.
Distribution, phytogeography, ecology. Warm Old World.
Species of open habitats.
Economic aspects. Significant weed species: C. parviflorum.
Hybrids. Intergeneric hybrids with Bothriochloa.
Rusts and smuts. Rusts Puccinia. Taxonomically wide-ranging species: Puccinia nakanishikii, Puccinia eritraeensis, Puccinia versicolor, Puccinia miyoshiana, and Puccinia cesatii. Smuts from Ustilaginaceae. Ustilaginaceae Sorosporium and Sphacelotheca.
References, etc. Leaf anatomical: Metcalfe 1960; studied by us - C. spicigerum Blake.
Illustrations. • C. assimile, as C. glaucopsis: Hook. Ic. Pl. 31 (1922). • C. parviflorum: Gardner, 1952. • C. picigerum, abaxial epidermis of leaf blade: this project. • C. spicigerum, T.S. 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: 11th December 2017. delta-intkey.com/grass’.