535 
1. B. dactyloides (Nutt.) Raf. (BurFrAaLo GRASS, ) Culms1to2 dm. high fromatufted 
leafy base, propagating chiefly by runners: leaves flat, 1 to 2 mm. wide, attenuate: 
staminate spikelets in pectinate spikes 1 em. long or less; pistillate spikelets (rare) 
in terminal or axillary clusters, subtended by inflated involucral sheaths (Sesleria 
dactyloides Nutt. Buchloe dactyloides Sngelm. )—Formerly one of the most important 
grasses of the plains'from Texas to Minnesota, but now rapidly disappearing, 
50. PAPPOPHORUM Schreb. 
Spikelets awn-shaped, 2 to 6-tlowered, the upper floret imperfect, often 
staminate, sessile and rather loosely arranged along the short branches 
of a narrowly pyramidal or spike-like panicle: empty glumes thin, per- 
sistent, the. second slightly larger; floral glume broad, convex, envel- 
oping the palet and broadly fusiform grain, 7 to 9-nerved; the nerves 
terminating in awns as long as the body and often with smaller inter- 
mediate aristiform lobes.—Annuals or perennials with rather rigid 
leaves, 
* Empty glumes I-nerved, equaling the florets, or shorter. 
1. P. apertum Munro, Culms erect, simple or sparingly branched below, 4 to 8 
dm. high, from a strongly rooted perennial base: leaves flat or involute, 1 to 3 dn. 
long, smooth except the pilose ligule: panicle narrowly pyramidal, 1 to 2 dm, long; 
branches 4 to 8 em. long, decreasing upward, slightly spreading: spikelets 4 to 
f-flowered, 6 to 8 mm. long, including the densely clustered awus; floral glume 
7-nerved, the nerves terminating in awns about as long as the body and with nearly 
as many aristiform lobes in the intervals.—Dry hills, western Texas. Var. VAGI- 
NATUM (Buckl.) Scribn. has culms more robust, panicle spike-like (usually vaginate 
at the base), branches shorter and closely appressed, and spikelets slightly larger, 
but otherwise like those of the species (P. vaginatum Buckley. P. apertum in “Grasses 
of the Southwest.” )—Western Texas to Arizona. 
“* Empty glumes 3 to 5-nerved, twice as long as the body of the florets. 
2. P. Wrightii Watson. Culms 2 to 4 dm. high, slender, branching, slightly bar- 
bellate at the nodes: leaves slender, 1 dm. long or less: panicle oblong, spike-like, 
often interrupted below, 5 to 10 em. long: spikelets 4 to 6 mm. long, including the 
awns, 2 to 3-flowered; floral glume with 9 nerves terminating in ciliate awns nearly 
twice as long as the glume.—Foothills and mesas, western Texas to Arizona, 
51. COTTEA Kth. 
Spikelets compressed, cuneate, 3 to 6-flowered, short-pedicelled in 
rather loose panicles: empty glumes subacute or 2 to 3-toothed, nearly 
equal, slightly shorter than the adjacent florets, 7 to 13-nerved; floral 
glume broad, convex, pubescent at the base, 9 to 11-nerved, terminating 
in as many unequal alternately mucronate and aristiform lobes; palet 
asNong as the body of the glume: grain smooth, oblong.—Erect peren- 
nials, with narrow attenuate flat leaves, 
1, C. pappophoroides Kth. Culms 3 to 6 din. high, sparingly branched, frem 
bulbiferous rootstocks: panicle oblong or pyramidal, hoary pubescent throughout; 
branches alternate, 3 to 5 cm. long, spreading, rather sparingly subdivided: spike- 
lets 6 to 8 nm. long.—Mountains and rocky canons, western Texas to Arizona and 
southward, 
