The grass genera of the world
Habit, vegetative morphology. Perennial; loosely caespitose. Culms 80–120 cm high; herbaceous. Culm internodes solid. Leaves without auricular setae. Leaf blades lanceolate; rolled; pseudopetiolate to not pseudopetiolate; cross veined. Ligule a fringed membrane.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence relatively few spikeleted; paniculate; open (broad, the branches thin and spreading); espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund.
Female-fertile spikelets. Spikelets 10–17 mm long; compressed laterally; disarticulating above the glumes (the glumes and the sterile basal floret persisting on the pedicel); disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; hairy (and sinuous). Hairy callus absent.
Glumes present; two; very unequal to more or less equal; shorter than the adjacent lemmas; hairless; pointed (sometimes mucronate); awnless; carinate; similar (herbaceous, the margins hyaline). Lower glume 3–5 nerved. Upper glume 3–5 nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets, or both distal and proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1; paleate, or epaleate (often); sterile. The proximal lemmas awned (subulate), or awnless; 5–7 nerved; exceeded by the female-fertile lemmas; similar in texture to the female-fertile lemmas; not becoming indurated.
Female-fertile florets 4–10. Lemmas similar in texture to the glumes (herbaceous); not becoming indurated; entire, or incised (slightly, at the tip); not deeply cleft; awned. Awns 1; median; from a sinus, or apical; non-geniculate; hairless to hairy; much shorter than the body of the lemma to about as long as the body of the lemma. Lemmas hairless (keels scabrid); glabrous (the keels scabrid); carinate; 5–7 nerved. Palea present; conspicuous but relatively short; entire; awnless, without apical setae; 2-nerved; 2-keeled (and hunch-backed, the keels ciliate; projecting from the lemma into sinuations of the rachilla). Lodicules present; 2; free; fleshy. Stamens 3. Ovary apically glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit free from both lemma and palea (but falling with them); compressed laterally (obliquely ovoid). Hilum short. Embryo large (about 1/3 of the fruit length); with an epiblast; with a scutellar tail; with an elongated mesocotyl internode. Embryonic leaf margins overlapping.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Mid-intercostal long-cells having markedly sinuous walls. Microhairs present (partly sunken); panicoid-type; 33–46 microns long. Microhair apical cells 26–30(–41) microns long. Microhair apical cell/total length ratio 0.75. Stomata common. Subsidiaries triangular. Intercostal short-cells absent or very rare. Costal short-cells conspicuously in long rows. Costal silica bodies panicoid-type; shortly dumb-bell shaped, or cross shaped.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with radiate chlorenchyma (indistinctly); without arm cells (?); without fusoids. Leaf blade adaxially flat. Midrib conspicuous (adaxially and abaxially projecting); having a conventional arc of bundles (the median flanked by 2 small laterals). Bulliforms present in discrete, regular adaxial groups. All the vascular bundles accompanied by sclerenchyma (exceptions near margins). Combined sclerenchyma girders present; forming figures (in the midrib). Sclerenchyma all associated with vascular bundles.
Culm anatomy. Culm internode bundles scattered.
Classification. Watson & Dallwitz (1994): Centothecoideae; Centotheceae. Soreng et al. (2015): Panicoideae; Chasmanthieae. 1 species.
Distribution, phytogeography, ecology. Angola.
Shade species; glycophytic. Forests.
References, etc. Leaf anatomical: Metcalfe 1960 and this project.
Illustrations. • B. gossweileri: Jacques-Félix, 1962
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’.