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Key to families | Table of families and genera

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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


James P. Smith, Jr. & Dieter H. Wilken

Annual. Stem: tufted, glabrous to puberulent. Leaf: ± basal; collar glabrous to puberulent; ligule < 1 mm, membranous; blade 0.3–14 cm, 0.3–2.5 mm wide, flat to rolled, upper generally much reduced. Inflorescence: panicle-like, open to dense. Spikelet: bisexual, laterally compressed, 1.5–4 mm; glumes > lower floret, translucent, keel scabrous; callus short-bristly; axis breaking above glumes and between florets; florets 2, fertile; lemma faintly 5-veined, generally glabrous, tip with 2 slender teeth, slightly scabrous, awned at or below middle, awn bent once or straight, exserted (occasionally reduced or 0 in lower floret) or straight; palea slightly < lemma; anthers 3.
8 species: southern Europe, Mediterranean, Africa, western Asia. (Greek: a weedy grass, perhaps a Lolium) [Wipff 2007 FNANM 24:615–617] Aira cupaniana Guss. [Aira caryophyllea var. cupaniana (Guss.) Fiori] was collected in Contra Costa Co. in 1995, but does not appear to have persisted.

Key to Aira

A. elegans Roem. & Schult. ELEGANT HAIR GRASS
Stem: 9–35 cm, generally glabrous. Leaf: sheath and ligule glabrous to slightly scabrous. Inflorescence: > 1.5 cm wide, open, branches not equal; spikelet stalk 2–8 × spikelet. Spikelet: 1.5–2.5 mm; glumes 1.5–2.5 mm; lemma ± 2 mm, awn ± 3 mm.
2n=14. Sandy to clay soils, open sites; generally < 400 m. Outer North Coast Ranges, n Sierra Nevada Foothills, Sacramento Valley, San Francisco Bay Area, w Western Transverse Ranges, Peninsular Ranges; to Washington, eastern and southern United States; native to southern Europe. [Aira elegantissima Schur; Aira caryophyllea L. var. capillaris Bluff, Nees, & Schauer; Aira pulchella Willd.] Also treated as Aira caryophyllea var. capillaris Bluff, Nees & Schauer, Aira elegantissima Schur, Aira pulchella Willd. Until the taxonomy of these European species is more clearly understood, it seems best to use Aira elegans as in Wipff 2007 FNANM 24:615–617. Apr–May [Online Interchange]
Unabridged note: Expanded author citation: Aira elegans Willd. ex Roem. & Schult.

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Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora,, accessed on Nov 30 2015
Citation for this treatment: [Author of taxon treatment] 2013. Aira, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on Nov 30 2015

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Geographic subdivisions indicated for the distribution of Aira elegans 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.
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.