Bothriochloa alta
Bothriochloa ischaemum
tall beardgrass, tall bluestem
King ranch bluestem, old world bluestem, yellow bluestem
1.3-2.5 m tall, 2-4 mm wide, stiffly erect, not or only sparingly branched;
nodes hirsute, hairs 2-6 mm, stiff, spreading, tan;
internodes glaucous below the nodes.
30-80(95) cm, stiffly erect;
nodes glabrous or short hirsute.
cauline;
ligules 1-3 mm;
blades 20-30 cm long, 4-10 mm wide, glabrous or sparsely pilose near the base.
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.
14-25 cm long on the larger shoots, 3-6 cm wide when pressed, oblong, dense;
rachises 10-20 cm, with numerous branches, rachises and branches kinked and wavy at the base from being compressed in the sheath;
branches 2-8 cm, much shorter than the rachises, erect to appressed, with multiple rames;
rame internodes villous on the margins, with 5-8 mm distal hairs.
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.
spikelets 4.5-6 mm, ovate;
lower glumes shortly pilose, with or without a dorsal pit;
awns 18-22 mm;
anthers about 1 mm, often remaining in the floret, light brown.
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.
spikelets 3.8-4.4 mm.
spikelets about as long as the sessile spikelets, but usually narrower, sterile or staminate.
= 120.
= 40, 50, 60.
Bothriochloa alta
Bothriochloa ischaemum
Bothriochloa alta grows along roads, drainage ways, and gravelly slopes in the desert grasslands of the south-western United States, at 600-1200 m, and extends south to Bolivia and Argentina. It is not a common species in the Flora region. It often grows with and is mistaken for B. barbinodis, but differs from that species in having longer culms, panicles, and nodal hairs, and 2n = 120. Plants in the southwestern United States have larger spikelets and more hairy panicles than those of central Mexico, where the species was originally described.
(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.)
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