Pleuraphis. GRAMINE.E. 293 



would indicate, as it extends from New England quite across the continent. It is found along 

 nearly the whole Atlantic coast, usually in brackish marshes, rarely over a foot high. The far- 

 western plant is more luxuriant, and the clustered spikelets give the panicle a denser appearance. 



2. L. imbricata, Thurber. Culms simple, erect, 1 or 2 feet high : leaves 6 to 8 

 inches long, 2 lines wide at base, setaceously acuminate, slightly scabrous ; sheaths 

 loose : panicle erect, 8 to 1 inches long, usually sheathed at base ; spikes very 

 numerous, solitary or fascicled, slightly spreading : spikelets appressed-imbricate, 

 nearly sessile, acute, 7 - 8-flowered, about 3 lines long : glumes very unequal, hispid 

 on the prominent solitary nerve, the lower narrow, acute, about half as long as the 

 lowest floret, the upper broader, obtuse, mucronate, more than a half longer : lower 

 palet about a line long, herbaceo-meinbranaceous, minutely 2-toothed at the obtuse 

 mucronate apex, the lateral nerves long-pilose below ; upper palet equalling the lower, 

 obtuse and denticulate at apex and hairy on the nerves : seed loose in the pericarp. 

 Gram. Mex. Bound, ined. 



Larken's Station, San Diego County (Palmer, n. 404) ; Fort Yuma (Major Thomas) ; and through 

 the Gila Valley to the Rio Grande. The lower leaves and sheaths are sometimes tinged with 

 purple, the panicle usually grayish green. Habit somewhat that of L. fascicularis, but the spikes 

 are much narrower, the spikelets being smaller, closely appressed and overlapping. In the shape 

 of the lower palet they are very distinct ; in place of the acute teeth and manifest awn of the 

 other, the teeth in this are minute and blunt and the midnerve produced only as a mere point. 



31. PLEURAPHIS, Torr. 



Panicle dense and spike-like. Spikelets in threes at the alternate notches of a 

 slender flexuose excavated rhachis, subtended by a tuft of hairs. Lateral spikelets 

 2 - 3-flowered, staminate ; central spikelet 1 - 2-flowered, perfect, flattened, broad, 

 membranous, with nearly equal cuneate glumes often 2-cleft at the apex and with 

 several (5 to 9) nerves, one or more excurrent below the tip as setae. Lower palet 

 3-5-nerved, cleft and short-awned above; upper 2-nerved and 2-toothed. Stamens 3, 

 with short filaments. Scales 2, ligulate, entire. Styles 2, very lolig, stigmatose with 

 simple hairs for the greater part of their length. Lateral spikelets narrow, similar to 

 the other in texture. Glumes 2-cleft or entire, 3 - 5-nerved, awned at or below the 

 apex. Palets nearly equal, toothed, the lower 3-nerved, the upper 2-nerved. Ann. 

 Lye. X. York, i. 148, t. 10; Watson, Bot. King. Exped. 381. 



A small genus of perennials, in several works placed with Chloridece, but its relationships are 

 rather with the Pappophorece. For a long time but a single species was known, but the discovery 

 of another, and perhaps two more, has rendered it necessary to so modify the character as to give 

 less importance to the setae upon the glumes, which in one probable species are nearly muticous. 

 The original species, P. JAMESII, Torr., 1. c., common in Nevada and the Rocky Mountain region, 

 and perhaps reaching Northeastern California, has slender culms which branch only near the base. 

 In Arizona and westward it is replaced by the species here described, and by P. mutica, Buckl. 



1. P. rigida, Thurber. Culms 2 feet high or more, erect, branching above, solid 

 throughout, clothed, especially within the sheaths, with a dense matted tomentum : 

 lower leaves 4 or 5 inches long, uppermost about an inch, rigid, mostly involute, 

 setaceous-pointed ; ligule very short, lacerate ; sheaths somewhat crowded, upper 

 very loose : panicle 3 or 4 inches long, mostly included at base, pale, tinged with 

 purple : glumes of central spikelet cuneate at base, bifid above, woolly-fringed, 3- or 

 indistinctly 5-nerved, the central nerve excurrent just below the middle as a stout 

 rough divergent awn a little exceeding the glume, the next two produced as setae 

 between the lobes and about equalling them : florets stipitate ; lower palet broad, 

 3-nerved, irregularly 2-toothed and fringed above, the awn slightly exceeding the 

 teeth ; upper palet somewhat the longer : glumes of lateral spikelets about equalling 

 the florets, irregularly toothed above, one or more nerves terminating as short straight 

 or recurved awns : palets of staminate florets nearly equal, the lower 3-nerved and 



