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Avena sterilis
ANIMATED OAT

Higher Taxonomy
Family: Poaceae (Gramineae)View DescriptionDichotomous Key

Common Name: GRASS FAMILY
Habit: 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.
Genera In Family: 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). Note: 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.
eFlora Treatment Author: James P. Smith, Jr., except as noted
Scientific Editor: James P. Smith, Jr., J. Travis Columbus, Dieter H. Wilken.
Genus: AvenaView DescriptionDichotomous Key

Common Name: OATS
Habit: 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.
Species In Genus: 29 species: temperate Europe, northern Africa, central Asia. Etymology: (Latin: oats) Note: 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.
eFlora Treatment Author: Bernard R. Baum, James P. Smith, Jr. & Dieter H. Wilken

Avena sterilis L.
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. Chromosomes: 2n=42.
Ecology: Disturbed sites; Elevation: 30--120 m. Bioregional Distribution: CCo (Alameda, Contra Costa cos.), SCo (San Diego Co.); Distribution Outside California: Canada, Pennsylvania, New Jersey; native Mediterranean to Afghanistan. Flowering Time: Mar--Jun Note: The awn twists with changes in humidity and moisture. Hybridizes with Avena sativa.
eFlora Treatment Author: Bernard R. Baum, James P. Smith, Jr. & Dieter H. Wilken
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Citation for this treatment: Bernard R. Baum, James P. Smith, Jr. & Dieter H. Wilken 2016. Avena sterilis, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=15325, accessed on May 31, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on May 31, 2016.


Avena sterilis
click for enlargement
© 2016 Keir Morse
Avena sterilis
click for enlargement
© 2016 Keir Morse
Avena sterilis
click for enlargement
© 2016 Keir Morse
Avena sterilis
click for enlargement
© 2016 Keir Morse
Avena sterilis
click for enlargement
© 2016 Keir Morse
Avena sterilis
click for enlargement
© 2016 Keir Morse

More photos of Avena sterilis in CalPhotos


Geographic subdivisions for Avena sterilis:
CCo (Alameda, Contra Costa cos.), SCo (San Diego Co.);
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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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.