46 PANICACE.E. 



on one edge of the stipe bearing luiirs 2 mm. long. Sessile spike- 

 let 7 mm. long; first glume flattened, O-nevved, ovate-ljineeohite 

 witli 2 ciliate keels; second glume shorter, thinner, keeled, 3-nerved; 

 third still shorter, hyaline; fourth bifid, bearing a twisted awn 1 em. 

 oi- more in length. Pedicellate spikelets 2—4 mm. long, consisting 

 of l-o empty glumes. 



Mexico, Wriyhf 2105, Primjic 382, Greene 400; Texas, Xe((l- 

 ley SnS. 



A neat slender grass found in Y. . :: Mexico, Arizona, and north- 

 ern Mexico. 



0. A. scoparius Michx. Fl. Bor. Am. 1 : 57 (1803). A. pirr- 

 jjnr(m-e)is Muhl. ; Willd. Sp. PI. 4 : 913 (180(i). 



Culms slender, (iO-OOcin. high, with numerous branches. Sheatlis 

 sparingly hairy; l)lades 2-3 mm. wide. Spikes slender, scattered, 

 usually 2-3 from a single sheath, exserted on slender i)edicels, the 

 joints of the rachis clothed on the two edges with lax dull-white 

 hairs. The sterile spikelet consists of a single glume al)out 3 mm. 

 long, or staminate aiul longer. First and second glumes of tlio 

 pistillate spikelet lanceolate, mm. long, and awn-pointed: first 

 glume fiattened on the back, scabrid, obscurely nerved; second 

 glume tliinner, keeled, 3-nerved ; fourth bifid for one third its 

 lengtli, bearing in the notch an awn 10-15 mm. long. 



From the Atlantic to the Rocky Mountains. \'ery common on 

 the prairies, aflFordiug considerable pasture; sometimes cut for hay. 

 It starts very late in tlie spring and is dunuiged 1)y frost. 



Subs[)ecies euscoparius Hack. D. C. Monog. I'han.. 1. c. Low 

 tufted; sheaths smooth; blades glaucous. scal)rous. 5-7 mm. wide; 

 first and secoiul glumes of sessile spikelet 8 mm. hiug, with points 

 2 mm. long. Specimens marked " teste E. Tlackel *' owned by F. 

 L. Scribner. Sandsof Cape May, N. J. Coll. J. Hurk, Oct. 2, 1888. 



Subspecies genuinus lla( k., 1. c. 



Pedicellate spikelets 2-3 mm. long, subulate; first glume 3- 

 nerved, terminating in a ])ristle; branches filiform, glabrous below 

 the nodes; racenu'S slender; very variable. ^lichigan (M. A. C. 3), 

 Coo/ei/, />m/o: Illinois, /inil 4; Penu.. .sVv//»av/' 3(135; Vt.. Priti' 

 ffh>; N. J., U. S. Ihpl. .i(/r}r. from Scriljuer 20(»; Texas, Xealleij. 



