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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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.

AVENA

OATS

Dieter H. Wilken

Annual
Stems erect, 1–6, ± glabrous
Leaves basal and cauline; ligules 2–5 mm, membranous, rounded at tip; blade flat
Inflorescence panicle-like, open
Spikelets generally stalked, ± pendent; glumes subequal, generally > florets, membranous, 5–7-veined, generally glabrous; axis prolonged behind upper floret, vestigial floret at tip; florets 2–3, upper floret > lower, bisexual, breaking above glumes and between florets or not breaking; lemmas hard, glabrous to hairy below awn, awned at or slightly below middle, tip 2-forked, 5–7-veined, awn stiff, bent to straight, slightly to strongly coiled below bend; palea ± < lemma
Species in genus: ± 10–15 species: temp Eur, Asia. Cult for grain, hay
Etymology: (Latin: oats)

Introduced

A. sativa L.

CULTIVATED OAT


Stem 4–9 dm
Leaf: blade 3–16 mm wide, minutely scabrous
Spikelet: glumes 15–30 mm, 7–9-veined; lemmas 12–25 mm, ± glabrous on back (sometimes stiff-hairy at base), tip acute to minutely 2-forked, forks < 1 mm, awn of upper floret 15–30 mm, straight, slightly twisted, awn of lower floret < 15 mm or 0
Chromosomes: 2n=42
Ecology: Disturbed sites
Elevation: 20–1100 m.
Bioregional distribution: California Floristic Province
Distribution outside California: to Alaska, eastern Canada, most of US; origin in Europe
Cult for grain; believed to be derived from wild A. fatua by early humans. Hybridizes with A. fatua.

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bioregional map for AVENA%20sativa being generated
 
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Retrieve Jepson Interchange Index to Plant Names entry for Avena sativa
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