Bothriochloa laguroides |
Bothriochloa ischaemum |
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silver beardgrass, silver bluestem |
King ranch bluestem, old world bluestem, yellow bluestem |
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Habit | Plants usually cespitose, occasionally stoloniferous or almost rhizomatous under close grazing or cutting. | |
Culms | 35-115(130) cm tall, usually less than 2 mm thick, erect or geniculate at the base, branched at maturity; nodes shortly hirsute, pilose with erect hairs, or glabrous. |
30-80(95) cm, stiffly erect; nodes glabrous or short hirsute. |
Leaves | usually basal (sometimes cauline on robust plants), usually glaucous; ligules 1-3 mm; blades 5-25 cm long, 2-7 mm wide, flat to folded, mostly glabrous. |
tending to be basal; ligules 0.5-1.5 mm; blades 5-25 cm long, 2-4.5 mm wide, flat to folded, glabrous or with long, scattered hairs at the base of the blade. |
Panicles | 4-12(14) cm, narrowly oblong or lanceolate, silvery-white or light tan; rachises 4-8 cm, with more than 10 branches; branches 1-5.5 cm, erect-appressed, rarely with axillary pulvini, lower branches shorter than the rachises, usually with more than 1 rame; rame internodes with a groove wider than the margins, margins copiously hairy, hairs 3-9 mm, at least somewhat obscuring the spikelets. |
5-10 cm, fan-shaped, silvery reddish-purple; rachises 0.5-2 cm, with (1)2-8 branches; branches 3-9 cm, longer than the rachises, erect to somewhat spreading from the axillary pulvini, usually with only 1 rame; rame internodes with a central groove narrower than the margins, margins ciliate, with 1-3 mm hairs. |
Sessile | spikelets 2.5-4.5 mm, ovate, somewhat glaucous, apices blunt; lower glumes glabrous or hirtellous, rarely with a dorsal pit; awns 8-16 mm; anthers 0.6-1.4 mm. |
spikelets 3-4.5 mm, narrowly ovate; lower glumes hirsute below, with about 1 mm hairs, lacking a dorsal pit; awns 9-17 mm, twisted, geniculate; anthers 1-2 mm. |
Pedicellate | spikelets 1.5-2.5(3.5) mm, shorter than the sessile spikelets, sterile. |
spikelets about as long as the sessile spikelets, but usually narrower, sterile or staminate. |
2n | = 60. |
= 40, 50, 60. |
Bothriochloa laguroides |
Bothriochloa ischaemum |
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Distribution |
AL; AR; AZ; CA; CO; FL; GA; IL; IN; KS; KY; LA; MO; MS; NE; NM; NV; OH; OK; SC; TN; TX; UT; HI
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AL; AR; AZ; CA; CO; FL; GA; KS; LA; MS; NM; NY; OH; OK; SC; TN; TX; UT; PR; Virgin Islands
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Discussion | Bothriochloa laguroides grows in well-drained soils of grasslands, prairies, roadsides, river bottoms, and woodlands, often on limestone, usually at 20-2100 m. Plants from the United States and northern Mexico belong to B. laguroides subsp. torreyana (Steud.) Allred & Gould, which differs from B. laguroides (DC.) Herter subsp. laguroides in its glabrous, or almost glabrous, nodes, long internode hairs, and pilose throat region. Occasional plants are found with spreading branches and axillary pulvini; they do not merit formal recognition. Bothriochloa laguroides subsp. torreyana is used in landscaping. It does well on rocky slopes and sandy banks. Bothriochloa laguroides has been confused with B. saccharoides (Sw.) Rydb., a more southern species that differs from B. laguroides in having pilose leaves, a narrow central groove in the internodes and pedicels, and panicle branches with axillary pulvini. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Bothriochloa ischaemum. grows along roadsides and in waste ground and rangeland pastures, at 50-1200 m. It is native to southern Europe and Asia. It was introduced to the United States for erosion control along right of ways and for livestock forage in the southwest. It is now established in the region and has spread along roadsides into other central and southern states. There are two variants that are sometimes recognized as varieties, plants with glabrous nodes being called B. ischaemum var. ischaemum and plants with pubescent nodes being called B. ischaemum var. songarica (Rupr. ex Fisch. & C.A. Mey.) Celarier & J.R. Harlan. The varieties are not recognized here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 25, p. 640. | FNA vol. 25, p. 646. |
Parent taxa | Poaceae > subfam. Panicoideae > tribe Andropogoneae > Bothriochloa | Poaceae > subfam. Panicoideae > tribe Andropogoneae > Bothriochloa |
Sibling taxa | ||
Synonyms | B. ischaemum var. songarica, Andropogon ischaemum var. songaricus, Andropogon ischaemum | |
Name authority | (DC.) Herter | (L.) Keng |
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