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.

SORGHUM

Kelly W. Allred

Annual, perennial herb, cespitose or with rhizomes
Stem erect; internodes generally solid
Leaves cauline; sheaths generally < internodes; ligule membranous; blades flat or folded
Inflorescence panicle-like, open to compact
Spikelets in pairs (trios at branch tips); lower sessile, bisexual; upper 1(2) stalked, staminate; pair with subtending axis segment falling as 1 unit
Sessile spikelet ovoid; lower glume leathery, shiny, glabrous to puberulent, enclosing upper glume, florets; florets 2, lower sterile, upper fertile; lemma membranous, fertile lemma awned, awn bent, twisted; palea < lemma
Species in genus: ± 20 species: tropical, subtropical, Africa. Cult for food, forage, sugar
Etymology: (Italian: Sorgho)
Reference: [de Wet 1978 Amer J Bot 65:477–484]