Andropogon gerardii
Andropogon hallii
Barbon de Gerard, big bluestem
sand bluestem
1-3 m, often glaucous.
(40)60-150(200) cm, strongly glaucous.
glabrous or pilose;
ligules 0.4-2.5 mm;
blades 5-50 cm long, (2)5-10 mm wide, usually pilose adaxially, at least near the collar.
usually only terminal;
peduncles with 2-6(10) rames;
rames 5-11 cm, exserted at maturity, usually purplish, sometimes yellowish;
internodes sparsely to densely pubescent, hairs 2.2-4.2 mm, usually white, rarely yellowish.
usually only terminal;
peduncles with 2-7 rames;
rames 4-7(9) cm, exserted at maturity;
internodes usually densely pubescent, hairs 3.7-6.6 mm, often strongly yellowish.
spikelets 5-11 mm, scabrous;
awns 8-25 mm;
anthers 3, 2.5-4.5 mm.
spikelets (5)6.5-12 mm;
lower glumes often ciliate;
awns absent or to 11 mm;
anthers 3, (2.3)4-6 mm.
spikelets 3.5-12 mm, usually well-developed and staminate.
spikelets 3.5-12 mm, usually well-developed and staminate.
(0.9)2.5-4.5 mm, ciliate;
blades 3-40(51) cm long, (1.5)2-10 mm wide, often pilose, at least near the collar.
= 20, 40, 60 (usually), 70, 80.
= 60 (usually), 70, 100.
Andropogon gerardii
Andropogon hallii
Andropogon gerardii grows in prairies, meadows, and generally dry soils. It is a widespread species, extending from southern Canada to Mexico, and was once dominant over much of its range. It is frequently planted for erosion control, restoration, or as an ornamental; the records from Washington and central Montana reflect such plantings. It hybridizes with A. ballii, the two sometimes being treated as conspecific subspecies.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Andropogon hallii grows on sandhills and in sandy soil. Its range extends through the central plains into northern Mexico. It is similar to A. gerardii, differing primarily in its rhizomatous habit, more densely pubescent rames and pedicels, and greater drought tolerance. Andropogon hallii and A. gerardii are sympatric in some locations. The two species can hybridize and are sometimes treated as conspecific subspecies.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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