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Key to families | Table of families and genera

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POACEAE (Gramineae) GRASS FAMILY

James P. Smith, Jr., except as noted

Annual to woody perennial herb; roots generally fibrous. Stem: generally round, hollow; nodes swollen, solid. Leaf: alternate, 2-ranked, generally linear, parallel-veined; 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; perianth vestigial; stamens generally 3; stigmas generally 2, generally plumose. Fruit: grain, sometimes achene- or utricle-like.
650–900 genera; ± 10550 species: worldwide; greatest economic importance of any family (wheat, rice, maize, millet, sorghum, sugar cane, forage crops, ornamental, weeds; thatching, weaving, building materials). [Barkworth et al. 2003 FNANM:25; Barkworth et al. 2007 FNANM:24] Generally wind-pollinated. Achnatherum, Ampelodesmos, Hesperostipa, Nassella, Piptatherum, Piptochaetium, Ptilagrostis moved to Stipa; Elytrigia, Leymus, Pascopyrum, Pseudoroegneria, Taeniatherum to Elymus; Hierochloe to Anthoxanthum; Lolium, Vulpia to Festuca; Lycurus to Muhlenbergia; Monanthochloe to Distichlis; Pleuraphis to Hilaria; Rhynchelytrum to Melinis. The following taxa (in genera not included here), recorded in California from historical collections or reported in literature, are extirpated, lacking vouchers, or not considered naturalized: Acrachne racemosa (Roth) Ohwi, Allolepis texana (Vasey) Soderstr. & H.F. Decker, Amphibromus nervosus (Hook. f.) Baill., Axonopus affinis Chase, Axonopus fissifolius (Raddi) Kuhlm., Coix lacryma-jobi L., Cutandia memphitica (Spreng.) K. Richt., Dinebra retroflexa (Vahl) Panz., Eremochloa ciliaris (L.) Merr., Eustachys distichophylla (Lag.) Nees, Gaudinia fragilis (L.) P. Beauv., Miscanthus sinensis Andersson, Neyraudia arundinacea (L.) Henrard, Phyllostachys aurea Rivière & C. Rivière, Phyllostachys bambusoides Siebold & Zuccarini, Rottboellia cochinchinensis (Lour.) Clayton, Schedonnardus paniculatus (Nutt.) Branner & Coville, Schizachyrium cirratum (Hack.) Wooton & Standl., Schizachyrium scoparium (Michx.) Nash, Themeda quadrivalvis (L.) Kuntze, Thysanolaena latifolia (Hornem.) Honda, Tribolium obliterum (Hemsl.) Renvoize, Zea mays L., Zizania palustris L. var. interior (Fassett) Dore, Zoysia japonica Steud. Paspalum pubiflorum E. Fourn., Paspalum quadrifarium Lam., are now reported for southern California (J Bot Res Inst Texas 4:761–770). See Glossary p. 30 for illustrations of general family characteristics. —Scientific Editors: James P. Smith, Jr., J. Travis Columbus, Dieter H. Wilken.
Unabridged references: [Hitchcock 1951 Manual grasses US, USDA Misc Publ 200; Clayton & Renvoise 1986 Kew Bull Add Series 13]

Key to Poaceae

AVENA OATS

Bernard R. Baum, James P. Smith, Jr. & Dieter H. Wilken

Annual. Stem: erect, 1–6, ± glabrous. Leaf: basal and cauline; ligule 2–5 mm, membranous, rounded at tip; blade flat. Inflorescence: panicle-like, open. Spikelet: 15–50 mm, laterally compressed, generally stalked, ± pendent; glumes unequal or ± equal, generally > florets, membranous, 3–11-veined, generally glabrous; axis occasionally prolonged behind upper floret, vestigial floret at tip; florets (1)2–6(8), 2+ bisexual, reduced florets distal to proximal ones, breaking above glumes and between florets or not; lemma hard, glabrous to hairy below awn, awned at or slightly below middle, 5–9-veined, tip 2-forked, forks ± tooth-like, awn stiff, generally bent, slightly to often strongly coiled below bend; palea ± < lemma; anthers 3. Fruit: cylindric, longitudinally grooved, pubescent.
29 species: temperate Europe, northern Africa, central Asia. (Latin: oats) [Baum 2007 FNANM 24:734–739] Cult for grain, hay. California records of Avena strigosa Schreb. are based on misidentifications of Avena barbata. California records of Avena occidentalis Durieu, are based on a misidentification of Avena fatua.
Unabridged references: [Baum 1977 Biosystematics Res Inst Monogr 14]

Key to Avena

A. sterilis L. ANIMATED OAT
NATURALIZED
Stem: 3–12 dm, becoming erect at maturity. Leaf: blade 8–60 cm, 4–8 mm wide, margins sparsely hairy. Spikelet: 24–50 mm; glumes 20–50 mm, 7–11-veined; callus bearded; florets 2–5, falling as a unit at maturity; lemma 18–40 mm, strigose below middle, forks at tip 1–1.5 mm, awn of lowest floret 35–90 mm, bent, twisted and short-hairy below bend.
2n=42. Disturbed sites; 30–120 m. Central Coast (Alameda, Contra Costa cos.), South Coast (San Diego Co.); Canada, Pennsylvania, New Jersey; native Mediterranean to Afghanistan. The awn twists with changes in humidity and moisture. Hybridizes with Avena sativa. Mar–Jun [Online Interchange]

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Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on Oct 22 2014
Citation for this treatment: [Author of taxon treatment] 2013. Avena, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=15325, accessed on Oct 22 2014

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Geographic subdivisions indicated for the distribution of Avena sterilis Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.