136 NORTH AMERICAN FLORA [VoLuME 17 
1.5-3 em. long; spikelet-clusters 5~6 mm. long, cuneate; empty scales of the lateral spikelets 
equaling or a little shorter than the cluster, the first scale unequally 2-lobed at the apex, 
3-4-nerved, the midnerve excurrent as a rather long awn between the lobes, the remaining 
nerves vanishing below the apex, or the longest one sometimes shortly exctrrent, the second 
scale when spread out one third as broad as long or less, 2-toothed at the apex, 4-nerved, the 
midnerve excturrent between the lobes as an awn about 0.5 mm: long, the remaining nerves 
vanishing below the obtuse apex; empty scales of the central spikelet 2-lobed to the middle, 
the hispid terete awn arising between the lobes, the margin of the lobes often bordered with a 
hispid nerve. 
TYPE LOCALITY : Mexico. 
DISTRIBUTION: Central Texas to Arizona, south to Chihuahua and Sonora. 
a es Bull. U. S. Dep. Agr. Bot. 121: £2. 10; Bull. U.S. Dep. Agr. Agrost. 7: f. 18; 
3. Hilaria ciliata (Scribn.) Nash. 
ae oe J. Presl, in Pres], Rel. Haenk. 1: 326. 1830. Not Hilaria cenchroides 
Hilarie een ae ciliata Scribn. Proc. Acad. Phila, 1891 : 293. 1891. 
Stems finally long and branching, up to 6 dm. long, glabrous or puberulent, the nodes 
usually barbed; leaf-sheaths glabrous, strongly nerved, much shorter than the longer blades; 
blades on the main stem often 2 dm. long, those on the branches much shorter, up to 6 mm. 
wide, rough, usually glabrous, or the upper surface with a few long hairs near the base; inflo- 
rescence 1.5—4 cm. long; spikelet-clusters 4-6 mm. long, the empty scales of the lateral spike- 
lets oblong-linear, 3-5-nerved, the nerves usually vanishing at or below the apex, very rarely 
excurrent as short points; empty scales of the central spikelet 2- or 3-lobed to about the middle, 
the inner lobe usually linear, obtuse, ciliate, the others with flat, stout, long-ciliate awns. 
TYPE LOCALITY : Near Guadalajara, Jalisco. 
DISTRIBUTION . Colima, Jalisco, and Tepic. 
ILLUSTRATION: Presl, Rel. Haenk. 1: pl. 45. 
32. PLEURAPHIS Torr. Ann. Lyc. N. Y. 1: 148. 1824. 
Perennial grasses with stout branching rootstocks, and the empty scales of the spikelet- 
clusters free, not united at the base, the flowering scale of the central spikelet not narrowed 
into a beak. Spikelets in sessile deciduous clusters of 3, the lateral spikelets 2- or 3-flowered, 
staminate, the central spikelet 1-flowered, perfect. Lateral spikelets with the empty scales 
usually unequal in length, awnless or awned, the first scale strongly inequilateral, 2-lobed, one 
lobe very narrow and often resembling a lateral rudiment, nerveless or rarely 1-nerved, the 
other lobe much broader, usually 3- or 4-nerved, the flowering scaJes compressed, commonly 
3-nerved, usually short-awned between the lobes. Central spikelet with the empty scales 
nearly equilateral, with 4-8 awns or awned lobes at the apex, and also with a long often dorsal 
awn, the flowering scale 3-nerved, usually short-awned between the lobes. Stamens 3. 
Stigmas shortly plumose. 
Type species, Pleuraphis Jamesii Torr. 
Leaves and stems glabrous, or at least not woolly ; stems simple. 
First scale of the lateral spikelets cuneate, longer than the second scale, flabel- 
lately nerved. 1. P. mutica. 
First scale of the lateral spikelets linear-oblong, shorter than the second scale, 
the nerves parallel. 2. P. Jamesiz. 
Leaves and stems densely woolly-pubescent ; stems branched. 3. P. rigida. 
1. Pleuraphis mutica Buckl. Proc. Acad. Phila. 1862: 95. 1862. 
Hilaria mutica Benth. Jour. Linn. Soc. 19: 62, 1881. 
Stems 2-6 dm. tall, simple, erect, smooth or sometimes rough below the puberulent 
nodes; leaves glabrous or hirsute, smooth or rough, confined mainly to the lower portion of 
the stem; sheaths overlapping; blades up to 8 cm. long, sometimes longer on the innovations, 
2-4 mm. wide, erect or ascending, usually involute on the margins; inflorescence 3.5-7 cm. 
long, the axis glabrous, sometimes hispidulous on the angles; spikelet-clusters 5.5-7.5 mm. 
long, 3-4 times as long as the basal hairs; lateral spikelets with the empty scales inequilateral, 
long-ciliate on the margins, 2-lobed, the first scale longer than the second, cuneate, flabellately 
