140 PAXICACE.E. 



Sj)ikelets smooth, oval or obovate, obtuse, 1.6-1.9 mm. long; 

 second and third glumes equal, 5-nerved; floret hispidulous, oval, 

 1.4 mm. long. 



Mexico (San Luis Potosi), Pringle 3817, Boiirg. 3035, Bott. 

 150, 151, 427, Bel. 390. 



Shady rocky slopes. 



64. P. depauperatum Muhl. (h-am. 112 (1817). P. Wilcox- 

 ianum Vasey, Bull. 8, U. S. Dept. Agric. Bot. Div. 32 (1889). 



A tufted 23erennial; culms slender, simple, erect, branching 

 below, 20-40 cm. high. Sheaths mostly pubescent; blades 3 to a 

 culm, narrowly linear, erect, flat or involute, beset with long soft 

 hairs. Panicle 3-6 cm. long, simple, contracted on long peduncles, 

 above the leaves or some of them much lower. Spikelets mostly 

 acute wheii young, some of them becoming obtuse when mature, 

 oval-ovate or oval-obovate, 2-3.5 mm. long; first glume 1-2 mm. 

 long, 1-5-nerved, second 7-10-nerved; floral glume of the neuter 

 spikelet 5-9-nerved, its palea small; fertile floret oval, smooth, 

 1.7-2.7 mm. long. 



Tlie plant varies much, especially the spikelets. In the above 

 measurement of spikelets the larger is from a plant collected by 

 Dr. A^asey in D. C, and named by Vasey & Scribner; the smaller 

 is one of the Cooly collection, from Deerfield, Mass. 



New York to Texas. Michigan, Wlieehr for M. A. C. 17, Beal 

 18, 19, CooJey for M. A. C. 20, 21; Massachusetts, Sturtevant; 

 Texas, Jenney for Nat. Mus., Xealley. 



Var. laxum Yasey, Bull. Torr. Club, 16:8 (1889). "Weaker 

 stemmed; panicle with longer and more spreading branches 

 (1.5-2 inclies), the lower ones single or verticillate ; spikelets 

 smaller." 



Virginia. Florida, Texas, Arkansas, Missouri. 



65. P. Vaseyanum Scribn. ined. 



A geniculate purplish branching annual. 50-80 cm. high, 

 smooth throughout, except the margins of the blades and the 

 hispid branches of the panicle; nodes light-colored. Sheaths loose, 

 ciliate; ligule very short; blades thin, flat, 10-15 cm. long, 4-6 

 mm. wide. Panicles terminal, or with two or three lateral, 



