POACEAE

GRASS FAMILY

James P. Smith, Jr., except as specified

Annual to bamboo-like; roots generally fibrous
Stem generally round, hollow; nodes swollen, solid
Leaves alternate, 2-ranked, generally linear; sheath generally open; ligule membranous or hairy, at blade base
Inflorescence various (of generally many spikelets)
Spikelet: glumes generally 2; florets (lemma, palea, flower) 1–many; lemma generally membranous, sometimes glume-like; palea generally ± transparent, ± enclosed by lemma
Flower generally bisexual, minute; stamens generally 3; stigmas generally 2, generally plumose
Fruit: achene-like grain
Genera in family: 650–900 genera; ± 10,000 species: worldwide; greatest economic importance of any family (wheat, rice, maize, millet, sorghum, sugar cane, forage crops, ornamental, weeds; thatching, weaving, building materials)
Reference: [Hitchcock 1951 Manual grasses US, USDA Misc Publ 200; Clayton & Renvoise 1986 Kew Bull Add Series 13]
See Glossary p. 26 for illustrations of general family characteristics. Generally wind-pollinated.

BOUTELOUA

GRAMA

J. Travis Columbus

Annual, perennial herb, generally cespitose
Stem solid, generally glabrous
Leaves generally basal; ligule generally < 1 mm, generally hairy; blade flat to inrolled, upper surface generally ± short-hairy, often ciliate near ligule, hairs long, bulbous-based
Inflorescence generally panicle-like; branches spike-like, 1 per node, persistent or deciduous in fruit; spikelets 2-rowed on 1 side of axis, overlapping
Spikelet sessile or short-stalked, ± cylindric to laterally compressed; glumes generally unequal, generally lanceolate, 1-veined, upper glume firmer than lower; axis (if inflorescence branch persistent) breaking between glumes and lower floret; florets generally 2–3, lower floret bisexual, > upper, upper florets generally vestigial, sterile; lemmas 3-veined, generally 3-awned, awns straight, scabrous; palea ± = lemma
Species in genus: ± 40 species: Am
Etymology: (Claudio (born 1774) and Esteban (born 1776) Boutelou, Spanish botanists, horticulturists)
Reference: [Gould 1979 Ann Missouri Bot Gard 66:348–416]
Many species important for forage.

Native

B. gracilis (Kunth) Griffiths

BLUE GRAMA

Perennial, generally short-rhizomed
Stem decumbent to erect, 1–6 dm
Leaf: blade < 15 cm, < 2 mm wide
Inflorescence: branches 1–4(6), 10–50 mm, spreading to appressed, persistent in fruit; branch axis terminated by vestigial spikelet, base hairy; spikelets 20–80 per branch, spreading to ascending, breaking apart between glumes and lower floret
Spikelet: upper glume 3.5–6 mm, vein generally with long, bulbous-based hairs, acute or awned < 0.5 mm; florets 2–3; lower floret lemma ± = upper glume, base hairy-tufted, back hairy, tip 2-lobed, awns 1–3 mm, unequal, central awn from sinus; base of middle or, if only 2 florets, upper floret hairy-tufted, lobed between awn bases, awns 2.5–6 mm, ± equal; uppermost floret (if present) < 2 mm, awn 0
Chromosomes: 2n=20, 21,28,35,40,42,60,61,77,84
Ecology: Sandy to rocky slopes, flats, drainages, scrub, woodland, pine forest
Elevation: < 2300 m.
Bioregional distribution: San Bernardino Mountains, e Desert Mountains (Ivanpah, New York, Clark mtns), waif elsewhere
Distribution outside California: to s Canada, e US, s Mexico, S.America
Flowering time: May–Aug
Horticultural information: DRN, SUN: 7, 15, 16, 17 &IRR: 2, 3, 8, 9, 14, 18, 19, 20, 21, 22, 23, 24; GRCVR; also STBL.