Panicum hallii
Panicum urvilleanum
Hall panicum, Hall's panic, Hall's panicgrass, Hall's panicum, Hall's witchgrass
desert panicgrass, silky panic grass
10-100 cm, 2-10 mm thick, erect, simple or sparingly branched basally;
nodes sericeous, pilose or glabrous;
internodes usually glaucous.
50-100 cm, erect, solitary or in small tufts from stout, scaly, creeping to vertical rhizomes or stolons, simple or branching at the base;
nodes densely villous.
densely villous;
ligules membranous, ciliate, hairs 1.5-2 mm;
blades 20-60 cm long, 4-10 mm wide, ascending to spreading, strigose to subglabrous, flat basally, tapering to a long, involute point.
often crowded basally;
sheaths rounded, glabrous or hirsute, hairs fragile, papillose-based, margins sometimes ciliate distally;
ligules 0.6-2 mm;
blades 4-23 cm long, 1-10 mm wide, erect to spreading, flat or sometimes involute (on sterile branches), often curling at maturity, glaucous, abaxial surfaces sometimes with prominent papillae along the midribs, bases rounded or narrowing to the sheaths, margins cartilaginous, ciliate basally, scabridulous elsewhere, apices acute.
20-30 cm long, 3-9 cm wide, narrow, shortly exserted;
branches slender, ascending;
secondary branches and pedicels 1-4 mm, crowded, ascending to appressed.
2.1-4.2 mm long, 0.8-1 mm wide, usually ovoid, glabrous.
5-7 mm, densely villous, hairs silvery or tawny-white.
1.2-2.4 mm, 1/2 - 3/4 as long as the spikelets, attenuate;
upper glumes and lower lemmas similar, 7-11-veined, acuminate, extending 0.3-1.2 mm beyond the upper florets;
lower florets sterile;
lower paleas 0.8-2 mm;
upper florets 1.5-2.4 mm long, 0.7-1.2 mm wide, ovoid to ellipsoid, smooth, nigrescent.
about 3/4 the length of the spikelets, 7-11-veined;
upper glumes and lower lemmas 7-15-veined;
lower florets staminate;
lower paleas about as long as the lower lemmas;
upper florets striate, margins of the upper lemmas villous, hairs white;
lodicules very large.
panicles 7-31 cm long, 3-15 cm wide;
rachises glabrous, tending to break at maturity;
branches usually alternate, slender, stiff, ascending to divergent;
pedicels 1-15 mm, appressed.
= 18.
= 36.
Panicum hallii
Panicum urvilleanum
Panicum hallii grows on sandy, gravelly, or rocky land, including roadsides, pastures, rangeland, oak and pine savannahs, chaparral, and moist areas in deserts and on mesas. Its range extends from the southwestern United States to southern Mexico.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Panicum urvilleanum grows on desert sand dunes and in creosote bush scrubland in the Mojave and Colorado desert regions of southern California, southern Nevada, and western Arizona. It also grows in Peru, Chile, and Argentina.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Spikelets 3-4.2 mm long; panicles usually greatly exceeding the blades, with a few spikelets; blades clustered near the base of the plants, ascending, often curling at maturity | subsp. hallii |
1. Spikelets 2.1-3 mm long; panicles scarcely exceeding the blades, with relatively crowded spikelets; blades not clustered near the base of the plants, lax, spreading, not curled | subsp. filipes |
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