The grass genera of the world
Habit, vegetative morphology. Slender perennial; rhizomatous. Culms 25–70 cm high; herbaceous. Culm nodes glabrous. Leaves non-auriculate. Sheath margins joined. Leaf blades linear; narrow; 3–6 mm wide; flat; not pseudopetiolate; persistent. Ligule an unfringed membrane; 0.1 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence a single raceme; espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund (but pendulous, falling to one side); pedicellate.
Female-fertile spikelets. Spikelets 10–30 mm long; compressed laterally; falling with the glumes (from the base of the pedicel). Rachilla prolonged beyond the uppermost female-fertile floret. Hairy callus absent.
Glumes two (narrow); very unequal; shorter than the spikelets; shorter than the adjacent lemmas; pointed (acuminate); awnless; similar (herbaceous). Lower glume 3 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 2; epaleate; sterile. The proximal lemmas acuminate; awnless; similar in texture to the female-fertile lemmas; not becoming indurated.
Female-fertile florets 1. Lemmas similar in texture to the glumes to decidedly firmer than the glumes (firmly herbaceous to thinly leathery); not becoming indurated; awned. Awns 1; median; dorsal; from near the top; non-geniculate; recurving (slightly bowed below, with a wing of green tissue extending from the upper back of the lemma to partway along awn). Lemmas carinate; 7 nerved. Palea present; relatively long; thinner than the lemma; 2-nerved (the keels closely adjacent); 2-keeled. Lodicules present (large, rectangular); 2; joined; membranous; glabrous; not toothed; not or scarcely vascularized. Stamens 3. Anthers 1.3–1.8 mm long. Ovary apically glabrous. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit free from both lemma and palea; with a thickened and glossy, umbonate cap. Hilum long-linear. Embryo small. Endosperm containing compound starch grains. Embryo with an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Mid-intercostal long-cells having markedly sinuous walls. Microhairs absent (and absent adaxially). Stomata absent or very rare. Intercostal short-cells common; in cork/silica-cell pairs (and solitary); silicified. Intercostal silica bodies tall-and-narrow. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous to horizontally-elongated smooth.
Transverse section of leaf blade, physiology. C3; XyMS+. Leaf blade with distinct, prominent adaxial ribs, or nodular in section; with the ribs more or less constant in size. Midrib conspicuous; with one bundle only. Bulliforms present in discrete, regular adaxial groups; in simple fans. All the vascular bundles accompanied by sclerenchyma.
Special diagnostic feature. Lemma awn winged, the wing extending down the upper back of the lemma.
Cytology. Chromosome base number, x = 10. 2n = 40. 4 ploid. Chromosomes medium sized.
Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Meliceae. Soreng et al. (2015): Pooideae; Brylkineae. 1 species (B. caudata).
Distribution, phytogeography, ecology. Japan, Manchuria, Sakhalin.
Mesophytic; shade species; glycophytic. Woodland.
References, etc. Morphological/taxonomic: Macfarlane and Watson 1980. Leaf anatomical: Metcalfe 1960, and studied by us.
Illustrations. • B. caudata: Flora of China 22 (2006)
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’.