The grass genera of the world
Including Diadranthus, Rubomons, Triarrhena (Maxim.) Nakai, Xiphagrostis Cov.
Excluding Miscanthidium, Sclerostachya
Habit, vegetative morphology. Perennial; rhizomatous and caespitose, or caespitose (usually tall, cane-like or reed-like). Culms 200–350 cm high; branched above, or unbranched above. The branching simple. Culm nodes hairy, or glabrous. Culm internodes solid. Leaves not basally aggregated; non-auriculate. Leaf blades broad, or narrow; flat; not pseudopetiolate; without cross venation; persistent; rolled in bud. Ligule a fringed membrane.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality; homomorphic.
Inflorescence. Inflorescence of spicate main branches and paniculate; open (the panicles large, fan-shaped or corymbiform, plumose); non-digitate; espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes racemes; persistent. Spikelets paired; not secund; pedicellate; consistently in long-and-short combinations; unequally pedicellate in each combination. The shorter spikelets hermaphrodite. The longer spikelets hermaphrodite.
Female-fertile spikelets. Spikelets compressed dorsiventrally; falling with the glumes (falling from their pedicels). Rachilla terminated by a female-fertile floret. Hairy callus present (with long fine hairs). Callus short; blunt.
Glumes two (papery to membranous); more or less equal; long relative to the adjacent lemmas; awnless. Lower glume 3–4 nerved. Upper glume 1–5 nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. The proximal incomplete florets 1; sterile. The proximal lemmas awnless; decidedly exceeding the female-fertile lemmas; not becoming indurated (hyaline).
Female-fertile florets 1. Lemmas usually becoming stiptate beneath an awn, but rarely reduced, hyaline and awnless; less firm than the glumes; not becoming indurated; entire, or incised; when incised, 2 lobed; not deeply cleft (bidentate); awnless (rarely), or awned. Awns 1; median; usually from a sinus; geniculate; hairless (glabrous); much shorter than the body of the lemma to much longer than the body of the lemma. Lemmas hairless; non-carinate; without a germination flap; 0–3 nerved. Palea present; conspicuous but relatively short; awnless, without apical setae; not indurated; nerveless. Lodicules present; 2; free; fleshy; glabrous. Stamens 2–3. Anthers not penicillate. Ovary apically glabrous. Styles free to their bases. Stigmas 2; red pigmented.
Fruit, embryo and seedling. Hilum short. Embryo large. Endosperm containing compound 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.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present. Intercostal papillae not over-arching the stomata; consisting of one oblique swelling per cell, or several per cell (finger-like). Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type; (48–)52–72(–77) microns long; 6.3–7.5 microns wide at the septum. Microhair total length/width at septum 8.2–9.4. Microhair apical cells 18–39 microns long. Microhair apical cell/total length ratio 0.42–0.53. Stomata common; 22–29 microns long. Subsidiaries low dome-shaped to triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells absent or very rare; in cork/silica-cell pairs, or not paired (solitary); silicified, or not silicified. Intercostal silica bodies when present, tall-and-narrow. Costal short-cells conspicuously in long rows. Costal silica bodies panicoid-type; cross shaped to dumb-bell shaped, or nodular; not sharp-pointed.
Transverse section of leaf blade, physiology. C4; XyMS. PCR cell chloroplasts with reduced grana. Mesophyll with radiate chlorenchyma; traversed by columns of colourless mesophyll cells. Leaf blade with distinct, prominent adaxial ribs (rarely), or adaxially flat; with the ribs more or less constant in size. Midrib conspicuous; having a conventional arc of bundles; with colourless mesophyll adaxially. Bulliforms present in discrete, regular adaxial groups; 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. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; nowhere forming figures. Sclerenchyma all associated with vascular bundles.
Phytochemistry. Leaves without flavonoid sulphates (3 species).
Cytology. Chromosome base number, x = 19. 2n = 35–43, or 57, 76, 95, and 114. Chromosomes small.
Classification. Watson & Dallwitz (1994): Panicoideae; Andropogonodae; Andropogoneae; Andropogoninae. Soreng et al. (2015): Panicoideae; Andropogonodae; Andropogoneae; Saccharinae. 20 species.
Distribution, phytogeography, ecology. Japan & Philippines.
Commonly adventive. Helophytic, or mesophytic; species of open habitats. Hillsides and marshes.
Economic aspects. Significant weed species: M. floridulus. Some (e.g. M. sinensis) cultivated a ornamentals; M. sinensis is the subject of extensive field trials as fuel and raw material for making paper and chipboard.
Hybrids. Intergeneric hybrids procured with Saccharum.
Rusts and smuts. Rusts Puccinia. Taxonomically wide-ranging species: Puccinia miscanthae. Smuts from Ustilaginaceae. Ustilaginaceae Sphacelotheca and Ustilago.
References, etc. Leaf anatomical: Metcalfe 1960; this project.
Illustrations. • M. ecklonii, as Erianthus capensis: Wood, Natal Plants 2 (1904). • General aspect (M. capensis): Gibbs Russell et al., 1990. • M. sinensis: Nicora & Rúgolo de Agrasar (1987)
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’.