Bromus diandrus |
Bromus |
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great brome, ripgut brome, ripgut grass |
brome, chess |
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Habit | Plants annual. | Plants perennial, annual, or biennial; usually cespitose, sometimes rhizomatous. | ||||||||||||||||||||
Culms | 20-90 cm, erect or decumbent, puberulent below the panicle. |
5-190 cm. |
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Sheaths | softly pilose, hairs often retrorse or spreading; auricles absent; ligules 2-3 mm, glabrous, obtuse, lacerate or erose; blades 3.5-27 cm long, 1-9 mm wide, both surfaces pilose. |
closed to near the top, usually pubescent; auricles sometimes present; ligules membranous, to 6 mm, usually erose or lacerate; blades usually flat, rarely involute. |
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Panicles | 13-25 cm long, 2-12 cm wide, erect to spreading; branches 1-7 cm, stiffly erect to ascending or spreading, with 1 or 2 spikelets. |
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Inflorescences | panicles, sometimes racemes in depauperate specimens, erect to nodding, open to dense, occasionally 1-sided; branches usually ascending to spreading, sometimes reflexed or drooping. |
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Spikelets | 25-70 mm, sides parallel or diverging distally, moderately laterally compressed, with 4-11 florets. |
5-70 mm, terete to laterally compressed, with 3-30 florets; disarticulation above the glumes, beneath the florets. |
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Glumes | smooth or scabrous, margins hyaline; lower glumes 15-25 mm, 1-3-veined; upper glumes 20-35 mm, 3-5-veined; lemmas 20-35 mm, linear-lanceolate, scabrous, 7-veined, rounded over the midvein, margins hyaline, apices bifid, acuminate, teeth 3-5 mm; awns 30-65 mm, straight, arising 1.5 mm or more below the lemma apices; anthers 0.5-1 mm. |
unequal, usually shorter than the adjacent lemmas, always shorter than the spikelets, glabrous or pubescent, usually acute, rarely mucronate; lower glumes 1-7(9)-veined; upper glumes 3-9(11)-veined; lemmas 5-13-veined, rounded to keeled, glabrous or pubescent, apices entire, emarginate, or toothed, usually terminally or subterminally awned, sometimes with 3 distinct awns or unawned; paleas usually shorter than the lemmas, ciliate on the keels, adnate to the caryopses; anthers (2)3. |
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x | = 7. |
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2n | = 42, 56. |
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Bromus diandrus |
Bromus |
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Distribution |
AR; AZ; CA; CO; DC; DE; GA; ID; IL; LA; MA; MD; MO; MT; NC; NJ; NM; NV; NY; OK; OR; SC; TX; UT; VA; WA; HI; BC
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AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; HI; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT; Greenland |
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Discussion | Bromus diandrus is native to southern and western Europe. It is now established in North America, where it grows in disturbed ground, waste places, fields, sand dunes, and limestone areas. It occurs from southwestern British Columbia to Baja California, Mexico, and eastward to Montana, Colorado, Texas, and scattered locations in the eastern United States. The common name 'ripgut grass' indicates the effect it has on animals if they consume the sharp, long-awned florets of this species. Bromus diandrus, as treated here, includes B. rigidus Roth. Sales (1993) reduced these two taxa to varietal rank, pointing out that the differences between them in panicle morphology and callus and scar shape are subtle enough that identification of many specimens beyond B. diandrus sensu lato is often impossible. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Bromus grows in temperate and cool regions. It is estimated to include 100-400 species, the number depending on how the species are circumscribed. Of the 52 species in the Flora region, 28 are native and 24 are introduced. The native perennial species provide considerable forage for grazing animals, with some species being cultivated for this purpose. The introduced species, all but three of which are annuals, range from sporadic introductions to well-established members of the region's flora. Many are weedy and occupy disturbed sites. Some are used for hay; others have sharp, pointed florets and long, rough awns that can injure grazing animals. This treatment is based on one submitted by Pavlick, who died before it could be reviewed and edited. It has been substantially revised by Anderton to meet the requirements for publication in this volume. The majority of Pavlick's taxonomic concepts are retained, despite the necessity for overlap in many key leads; time constraints prevented a thorough investigation of problematic taxa. The treatment recognizes taxa at both the subspecies and varietal rank; this simply reflects the decisions of the original author. We thank Hildemar Scholz of the Botanic Garden and Botanical Museum Berlin-Dahlem, Free University Berlin, for providing accurately identified specimens of the weedy European species for use in preparing the illustrations, and for his helpful suggestions for the keys and descriptions. In the keys and descriptions, the distances from the bases of the subterminal lemma awns to the lemma apices are measured on the most distal florets in a spikelet. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 24, p. 224. | FNA vol. 24, p. 193. | ||||||||||||||||||||
Parent taxa | Poaceae > subfam. Pooideae > tribe Bromeae > Bromus > sect. Genea | Poaceae > subfam. Pooideae > tribe Bromeae | ||||||||||||||||||||
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Subordinate taxa | ||||||||||||||||||||||
Synonyms | B. rigidus var. gussonei, B. rigidus, Anisantha diandra | |||||||||||||||||||||
Name authority | Roth | L. | ||||||||||||||||||||
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