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Arrhenatherum elatius

Higher Taxonomy
Family: Poaceae (Gramineae)View DescriptionDichotomous Key

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: ArrhenatherumView Description 

Common Name: OAT GRASS
Habit: Perennial herb, generally cespitose. Stem: erect, basal internodes sometimes bulbous. Leaf: basal and cauline; ligule membranous, obtuse, minutely soft-hairy; blade flat, soft-hairy. Inflorescence: panicle-like, narrow, branches spreading until after flower. Spikelet: laterally compressed; glumes unequal, keeled, acute, lower 1- or 3-veined, upper 3-veined; florets 2, lower < upper, lower generally staminate, upper pistillate or bisexual, breaking above glumes, falling as 1 unit; callus hairy; lemma keeled, 5--7-veined, lemma of lower floret awned below middle, awn bent, twisted, upper lemma awnless or awned at tip, awn straight; palea < lemma.
Species In Genus: 6 species: temperate Europe, Asia. Etymology: (Greek: masculine awn, with reference to awned staminate floret)
eFlora Treatment Author: James P. Smith, Jr. & Dieter H. Wilken
Reference: Hatch 2007 FNANM 24:740--742

Arrhenatherum elatius (L.) J. Presl & C. Presl
Habit: Perennial herb, cespitose, sometimes rhizomatous. Stem: ascending to erect, 5--15(18) dm, basal internodes bulbous or not. Leaf: ligule 1--3 mm, obtuse, minutely ciliate; blade 5--30 cm, 3--8 mm wide, flat, glabrous to minutely scabrous. Inflorescence: 7--30 cm, 1--6 cm wide. Spikelet: subsessile to stalked; lower glume 4--7 mm, upper 7--10 mm, glume margins translucent, keel soft-hairy; lemma 6--9 mm, awn of lower lemma 10--17 mm, awn of upper < 4 mm (sometimes 0); palea translucent. Chromosomes: 2n=14,28,42.
Ecology: Disturbed, open sites; Elevation: 30--1800 m. Bioregional Distribution: NW, CaR, n&c SNF, c SNH, CCo, SnFrB, WTR, MP; Distribution Outside California: to Alaska, southern Canada, most of United States; native to temperate Europe. Flowering Time: May--Jul Note: Grown for forage; variegated forms cultivated as ornamental.
Synonyms: Arrhenatherum elatius subsp. bulbosum (Willd.) Schöbl. & G. Martens; Arrhenatherum elatius var. biaristatum (Peterm.) Peterm.; Arrhenatherum elatius var. bulbosum (Willd.) Spenn.;
eFlora Treatment Author: James P. Smith, Jr. & Dieter H. Wilken
Reference: Hatch 2007 FNANM 24:740--742
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botanical illustration including Arrhenatherum elatius


Citation for this treatment: James P. Smith, Jr. & Dieter H. Wilken 2012, Arrhenatherum elatius, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on October 18, 2018.

Citation for the whole project: Jepson Flora Project (eds.) 2018, Jepson eFlora,, accessed on October 18, 2018.

Geographic subdivisions for Arrhenatherum elatius:
NW, CaR, n&c SNF, c SNH, CCo, SnFrB, WTR, MP;
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.
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, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time.