The grass genera of the world
Named for Johann Beckmann.
Including Buchmannia Nutt, Joachima Ten.
Habit, vegetative morphology. Annual, or perennial; rhizomatous, or caespitose. Culms 30–150 cm high; herbaceous; tuberous (when perennial), or not tuberous. Culm internodes hollow. Leaves non-auriculate. Leaf blades narrow; 4–10 mm wide; flat; without cross venation; rolled in bud. Ligule an unfringed membrane; not truncate (acute); 5–10 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets; outbreeding.
Inflorescence. Inflorescence of spicate main branches, or paniculate (the branches sometimes themselves branched); open; non-digitate (branches racemosely arranged); espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets secund (the branches unilateral); biseriate.
Female-fertile spikelets. Spikelets 1.5–4 mm long; suborbicular; compressed laterally; falling with the glumes. Rachilla prolonged beyond the uppermost female-fertile floret, or terminated by a female-fertile floret; the rachilla extension when present, with incomplete florets. Hairy callus absent.
Glumes two; more or less equal; long relative to the adjacent lemmas; conspicuously ventricose to not ventricose; pointed; awnless (but mucronate); carinate; similar (herbaceous, navicular, more or less inflated, cross-veined). Lower glume 3 nerved. Upper glume 3 nerved. Spikelets with female-fertile florets only, or with incomplete florets. The incomplete florets when present, distal to the female-fertile florets. The distal incomplete florets 1 (male). Spikelets without proximal incomplete florets.
Female-fertile florets 1, or 2. Lemmas acuminate; cartilaginous; not becoming indurated; entire; pointed; awnless, or mucronate; hairy, or hairless; non-carinate (dorsally rounded); without a germination flap; 5 nerved. Palea present; relatively long; 2-nerved; 2-keeled, or keel-less. Lodicules present; 2; free; membranous; glabrous; toothed, or not toothed; not or scarcely vascularized. Stamens 3. Anthers 0.4–1.8 mm long. Ovary glabrous. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit small (1.6–2 mm long); not noticeably compressed. Hilum short. Embryo small. Endosperm liquid in the mature fruit; with lipid. 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. Long-cells markedly different in shape costally and intercostally; differing markedly in wall thickness costally and intercostally. Mid-intercostal long-cells fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata common. Subsidiaries low dome-shaped, or parallel-sided. Guard-cells overlapped by the interstomatals (mostly, slightly). Intercostal short-cells absent or very rare. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous, or rounded, or crescentic.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma.
Cytology. Chromosome base number, x = 7. 2n = 14 (usually), or 16. 2 ploid. Chromosomes large.
Taxonomy. Pooideae; Poodae; Aveneae.
Distribution, ecology, phytogeography. 2 species; North Eurasia & North America. Helophytic, or mesophytic; species of open habitats. Meadows, etc.
Holarctic. Boreal, Tethyan, and Madrean. Arctic and Subarctic, Euro-Siberian, Eastern Asian, Atlantic North American, and Rocky Mountains. Mediterranean and Irano-Turanian. European and Siberian. Canadian-Appalachian, Southern Atlantic North American, and Central Grasslands.
Rusts and smuts. Rusts Puccinia. Taxonomically wide-ranging species: Puccinia graminis, Puccinia coronata, and Puccinia striiformis. Smuts from Tilletiaceae and from Ustilaginaceae. Tilletiaceae Urocystis. Ustilaginaceae Ustilago.
Economic importance. Important native pasture species: B. syzigachne.
References, etc. Leaf anatomical: this project.
Illustrations. • B. syzigacne: Hitchcock & Chase (1950)
The descriptions are offered for casual browsing only. We strongly advise against extracting comparative information from them. This is much more easily achieved using 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, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG).
Cite this publication as: ‘Watson, L., 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: 7th December 2015. delta-intkey.com’.