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Bromus diandrus

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: BromusView DescriptionDichotomous Key

Common Name: BROME, CHESS
Habit: Annual to perennial herb. Leaf: basal and cauline; sheath closed to near top, hairy or glabrous; ligule <= 7 mm, membranous, entire to fringed; blade flat to inrolled. Inflorescence: generally raceme- or panicle-like, open to dense; pedicels generally stiff, rigid. Spikelet: strongly laterally compressed to cylindric; florets 3--30; axis breaking above glumes and between florets; glumes unequal, generally < lower floret, lower 1--3-veined, upper 3--7-veined, back rounded to strongly keeled, tip acute; lemma 5--9-veined, tip 2-toothed or entire, acute to obtuse, awned from between teeth or awns 0; palea generally < lemma.
Species In Genus: +- 160 species: temperate worldwide. Etymology: (Greek: ancient name) Note: Bromus scoparius L., Bromus erectus Huds. not known to be naturalized in California. Bromus pacificus Shear not in California.
Unabridged Note: Report in FNANM of Bromus pacificus Shear (in HSC) based on misidentification.
eFlora Treatment Author: Jeffery M. Saarela & Paul M. Peterson

Bromus diandrus Roth
Habit: Annual 15--120 cm. Leaf: sheath glabrous or hairy; ligule 1--3 mm; blade 2--7 mm wide, hairy. Inflorescence: 6--25 cm, +- open; lower branches generally nodding, upper branches spreading to ascending; inflorescence branches generally 1, < or > spikelets, lower (longest) 1-branched. Spikelet: 25--70 mm, not strongly flattened; glumes glabrous to scabrous, lower 12--25 mm, 1(3)-veined, upper 18--35 mm, 3(5)-veined; florets 5--8; lemma 18--35 mm, 1--2 mm wide, back rounded, teeth 3--7 mm, awn 30--65 mm, straight; anthers 0.5--1.3 mm. Chromosomes: 2n=28,42,56.
Ecology: Open, generally disturbed areas; Elevation: < 2170 m. Bioregional Distribution: CA; Distribution Outside California: to British Columbia, Colorado, Texas, South America; native to Europe. Flowering Time: Feb--Jul
Synonyms: Bromus rigidus Roth; Bromus diandrus var. rigidus (Roth) Sales
eFlora Treatment Author: Jeffery M. Saarela & Paul M. Peterson
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Citation for this treatment: Jeffery M. Saarela & Paul M. Peterson 2016. Bromus diandrus, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on October 21, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on October 21, 2016.

Bromus diandrus
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© 2004 Carol W. Witham
Bromus diandrus
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© 2009 Keir Morse
Bromus diandrus
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© 2008 Thomas Stoughton
Bromus diandrus
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© 2013 Julie Kierstead Nelson
Bromus diandrus
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© 2009 Neal Kramer
Bromus diandrus
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© 2009 Neal Kramer

More photos of Bromus diandrus in CalPhotos

Geographic subdivisions for Bromus diandrus:
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).

View elevation by latitude chart
Data provided by the participants of the Consortium of California Herbaria.
View all CCH records

CCH collections by month

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