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.

ACHNATHERUM

NEEDLEGRASS

Mary E. Barkworth

Perennial, tufted
Stem generally erect
Leaf: ligule membranous, sometimes long-ciliate, blade generally flat
Inflorescence panicle-like, generally narrow; branches generally ascending
Spikelet: glumes > floret (except awn), tapered below midpoint; axis breaking above glumes; floret 1, generally cylindric; callus blunt or sharp, hairs stiff; lemma stiffly membranous to hard, evenly hairy or glabrous above, awned from tip; awn > 10 mm, persistent, with 1–2 bends, or < 10 mm, readily deciduous, ± straight; palea < lemma, hairy, veined
Species in genus: ± 75 species: temp worldwide
Etymology: (Greek: awned scale, from lemma)
Segregated mostly from Stipa ; see also Hesperostipa, Nassella.

Native

A. occidentale (Thurb.) Barkworth


Stem 2–12 dm
Leaf glabrous to hairy; sheath generally ciliate at top; blade 0.5–1 mm wide, generally rolled
Inflorescence 8–30 cm
Spikelet: glumes 9–15 mm, ± equal; floret 5.5–7.5 mm; callus sharp; lemma 1.6–3 X palea length, hairs short; awn 15–40 mm, bent twice, lower 2 segments hairy
Chromosomes: 2n=36
Ecology: Open, dry sites, sagebrush scrub, coniferous forest, alpine
Elevation: 150–3400 m.
Bioregional distribution: Klamath Ranges, Cascade Range, Sierra Nevada, San Bernardino Mountains, Peninsular Ranges, Great Basin Floristic Province
Distribution outside California: to Washington, Idaho, Utah

Native

subsp. pubescens (Vasey) Barkworth


Spikelet: lemma tip hairs generally = awn hairs, distal awn segment smooth to slightly rough
Ecology: Sagebrush scrub, coniferous forest
Elevation: 150–3100 m.
Bioregional distribution: Klamath Ranges, Cascade Range, Sierra Nevada, San Bernardino Mountains
Distribution outside California: to Washington, Idaho, Utah
Synonyms: Stipa elmeri Scribner
Horticultural information: DRN: 1, 15, 16, 24 &SHD: 2, 3, 7, 14, 18, 19, 20, 21, 22, 23; STBL.

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