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.

SPOROBOLUS

DROPSEED, SACATON

Michael Curto

Annual, perennial herb
Stems generally ascending to erect, 2–20 dm, generally tufted, ± solid in X -section
Leaves generally basal; cauline few, ascending or curving away; distal sheath margin and collar glabrous or hairy; ligule < 1 mm, hairy or membranous, fringed; blade flat to inrolled, generally glabrous or scabrous, sometimes short-soft-hairy
Inflorescence terminal, also sometimes axillary, panicle- or spike-like, generally partly enclosed by sheath; branches spreading or appressed
Spikelet < 6 mm, generally pale to gray-green or purplish; glumes generally unequal, upper < or > lemma, membranous to translucent, 1-veined; floret bisexual, generally breaking above glumes; lemma texture generally like glumes, 1(3)-veined; palea < or > lemma
Fruit 1–3 mm, generally falling from floret, generally gelatinous when wet
Species in genus: ± 150 species: Am, Eurasia, Africa
Etymology: (Greek: to throw seed, from deciduous seeds)