Brachyelytrum P. Beauv.
From the Greek brachus (short) and elutron (cover, husk), alluding to short glumes.
Habit, vegetative morphology. Slender perennial; with short, knotty rhizomes. Culms 50–100 cm high; herbaceous. Culm nodes hairy, or glabrous. Culm internodes solid. Leaves non-auriculate. Leaf blades narrowly lanceolate; broad; 10–22 mm wide; pseudopetiolate (basally constricted), or not pseudopetiolate; cross veined, or without cross venation; persistent; rolled in bud; ligule present; an unfringed membrane to a fringed membrane; 1.7–3.5 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate (scanty); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 7–12 mm long; not noticeably compressed to compressed dorsiventrally; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; hairy; the rachilla extension naked (bristle-like). Hairy callus present.
Glumes present; two, or one per spikelet (the lower sometimes vestigial or absent); (the upper, larger), minute to relatively large; very unequal; shorter than the adjacent lemmas (the upper no more than about 1/4 of the floret length); awnless. Lower glume 0–1 nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas tapering into the awn; herbaceous; not becoming indurated; entire; pointed; awned. Awns 1; median; apical; non-geniculate; hairless (scabrid); much longer than the body of the lemma; entered by several veins (3). Lemmas hairless; scabrous; non-carinate (rounded on the back); 5 nerved. Palea present; relatively long; convolute; 2-nerved; slightly 2-keeled. Lodicules present; 2; free; membranous; glabrous; not toothed; heavily vascularized. Stamens 3. Ovary hairy; without a conspicuous apical appendage (but narrow and hairy above). Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit small to medium sized (5 mm long); linear; longitudinally grooved; compressed dorsiventrally. Hilum long-linear. Pericarp thick and hard; loosely adherent to fused (removable with difficulty). Embryo small; not waisted. Endosperm hard (Soreng and Davis, 1998); containing only simple starch grains (these relatively large). Embryo with an epiblast; with a scutellar tail, or without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins overlapping.
Seedling with a short mesocotyl. First seedling leaf with a well-developed lamina. The lamina narrow; curved; 11–13 veined.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present; intercostal. Intercostal papillae not over-arching the stomata; often several per cell (large, irregular in shape). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs absent. Stomata common. Subsidiaries non-papillate; parallel-sided. Guard-cells overlapped by the interstomatals (slightly), or overlapping to flush with the interstomatals. Intercostal short-cells absent or very rare. Costal short-cells conspicuously in long rows. Costal silica bodies ‘panicoid-type’.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without arm cells; without fusoids. Leaf blade adaxially flat. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups; in simple fans. Many of the smallest vascular bundles unaccompanied by sclerenchyma. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 11. 2n = 22. 2 ploid.
Taxonomy. Stipoideae (or Bambusoideae?); Brachyelytreae.
Distribution, ecology, phytogeography. 1 species; North America, Japan & Korea. Shade species. Woodland.
Holarctic. Boreal. Eastern Asian and Atlantic North American. Canadian-Appalachian and Southern Atlantic North American.
References, etc. Morphological/taxonomic: Macfarlane and Watson 1980; Campbell, Garwood and Specht 1985. Leaf anatomical: this project.
Cite this publication as: Watson, L., and Dallwitz, M. J. (1992 onwards). ‘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.’ http://biodiversity.uno.edu/delta/. Version: 18th August 1999. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1998), and Watson and Dallwitz (1994), and Watson, Dallwitz, and Johnston (1986) should also be cited (see References).