Jepson Flora Project: Jepson Interchange    

 
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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California

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  • Up-to-date information about California vascular plants is available from the Jepson eFlora.

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.

HETEROPOGON

Kelly W. Allred

Annual, perennial herb, cespitose
Stem erect, densely clumped
Leaves cauline; sheaths flattened, generally < internodes; ligule truncate, thinly membranous; blade flat or folded
Inflorescence ± spike-like
Spikelets on 1 side of axis, paired; spikelets of lower 1–4 pairs ± equal, sterile or staminate; spikelets of upper pairs strongly unequal, lower spikelet sessile, bisexual, awned, upper stalked, staminate or sterile, awn 0, pair breaking below sessile spikelet
Sessile spikelet: glumes hard, short-hairy, tightly enclosing florets; florets 2, lower vestigial, obscure, upper fertile; lemma transparent, fragile
Stalked spikelet: glumes, lemmas thinly membranous
Species in genus: 6 species: warm temp, tropical
Etymology: (Greek: different beard, from awned and awnless spikelets)

Native

H. contortus (L.) Roem. & Schult.

Perennial
Stem 2–8 dm
Leaf: blade 6–24 cm, 4–8 mm wide
Inflorescence 4–8 cm
Sessile spikelet: glume 5–8 mm, dark brown, sharp-pointed, callus hairs red-brown, awn 5–10 cm, puberulent, red-brown
Stalked spikelet staminate
Chromosomes: 2n=60
Ecology: Uncommon. Rocky slopes, washes, open areas
Elevation: < 800 m.
Bioregional distribution: Sonoran Desert, naturalized in South Coast (San Diego Co.)
Distribution outside California: Baja California, to s US, worldwide
Weedy.

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