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.

DESCHAMPSIA

HAIRGRASS

Dieter H. Wilken and Elizabeth Painter

Annual, perennial herb
Stems erect, solitary to densely clumped
Leaves basal to cauline; ligule narrow, decurrent to sheath, glabrous to minutely hairy; blades flat to inrolled
Inflorescence panicle- to spike-like, open to narrow
Spikelet: glumes and lemmas shiny; glumes equal to ± subequal, > lower floret; axis prolonged beyond upper floret, bristly (sometimes with vestigial floret at tip); florets 1–3, bisexual, breaking above glumes and between florets; callus soft-hairy; lemmas rounded, 2–4-toothed at truncate tip, faintly 3–7-veined, awned at or below middle, awn straight to bent; palea ± = lemma
Species in genus: 30–40 species: temp Am, Eurasia, New Zealand, Antarctica
Etymology: (J. L-Deslongchamps, France, born 1774)

Native

D. danthonioides (Trin.) Munro

ANNUAL HAIRGRASS

Annual
Stems generally solitary to loosely clumped, 1.2–6 dm
Leaves generally basal, glabrous; ligule 2–4 mm, acute to acuminate, entire; blades 1–9 cm, 1–2 mm wide, generally inrolled
Inflorescence narrow to open; lower branches generally ascending
Spikelet: glume and lemma tips sometimes purplish; glumes 4–9 mm, equal, lanceolate, acute to acuminate, 3-veined; florets generally 2; callus hairs < 1/2 lemma length; lemmas 2–3 mm, generally 2–3-toothed at tip, faintly 1–3-veined, awned below middle, awn 4–9 mm, slightly bent
Chromosomes: 2n=26
Ecology: Moist to drying, open sites, meadows, streambanks, temporary ponds
Elevation: < 2700 m.
Bioregional distribution: California Floristic Province, Modoc Plateau, Desert Mountains (uncommon)
Distribution outside California: to Alaska, Arizona, Baja California, S.America
Flowering time: Mar–Aug
Horticultural information: SUN, IRR: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24.