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.

BROMUS

BROME

Dieter H. Wilken and Elizabeth L. Painter

Annual to perennial herb
Leaves basal and cauline; sheath closed, generally hairy; ligule generally < 5 mm, membranous, entire to fringed; blade flat to inrolled
Inflorescence generally panicle-like, open to dense; spikelet stalk generally stiff, rigid
Spikelet strongly compressed to cylindric; axis breaking above glumes and between florets; glumes unequal, generally < lower floret, lower generally 1–3-veined, upper 3–7-veined, back rounded to keeled, tip acute; lemmas faintly 5–9-veined, tip generally 2-toothed, short-pointed to straight-awned from between teeth; palea generally < lemma
Species in genus: ± 150 species: temp worldwide
Etymology: (Greek: ancient name)
Reference: [Stebbins 1947 Contr Gray Herb 165:42–55; Wagnon 1952 Brittonia 7:415–480]
Native species need careful study.

Native

B. carinatus Hook. & Arn.

CALIFORNIA BROME

Perennial 45–150 cm, sometimes flowering first yr
Leaf: sheath glabrous to soft-hairy; blade 3–12 mm wide, glabrous, scabrous, or soft-hairy
Inflorescence 5–20 cm, ± dense, generally becoming open in fruit; lowest branches generally spreading to ascending; upper branches ascending to erect
Spikelet strongly compressed; glumes keel-like, glabrous to short-soft-hairy, lower 6.5–12 mm, generally 3-veined, upper 9–15 mm, 5–7(9)-veined; florets 7–11; lemma body 12–17 mm, 7–9-veined, keel-like, glabrous to densely short-hairy, awn 3–15 mm
Chromosomes: 2n=56
Ecology: Open scrub, woodland, coniferous forest
Elevation: < 3500 m.
Bioregional distribution: California (except Great Central Valley, Sonoran Desert)
Distribution outside California: to Alaska, Texas, n Mexico
Plants generally self-pollinating, florets often cleistogamous; forms formerly recognized as species widespread, often occurring together.

Native

var. carinatus

Inflorescence: spikelets not crowded or overlapping; branches and stalks generally > spikelets
Ecology: Habitat and range of sp
Elevation:
Bioregional distribution: California (except Great Central Valley, Sonoran Desert)
Flowering time: Apr–Aug
Synonyms: B. breviaristatus Buckley; B. marginatus Steudel; B. polyanthus Scribner, Great Basin brome
Plants from NCo with leaf blade generally > 10 mm wide, spikelets 1–2 per branch, may be B. sitchensis Trin
Horticultural information: STBL; CVS.