Cijiwilon. GRAMINE.E. 291 



^^ Sj)ikcs pectinatclij mnnij-Jiowcn'tl, erect or ajnrtuJinij, tlie rhachis not proloncjcd 

 beyond tlic spikclcts. 



1. B. oligOStachiya, Torr. Pcrcimial, G to 18 inches liif^h : leaves smooth or 

 biiivly roughened ahuve : si)ikes 1 to T), remote, 1 to li inches long, often much 

 curved, on very sliort iiairy pedicels; rhachis smooth or sparingly hairy : spikelets 

 (including setre) about 3 lines long : glumes (tlie upper 2 lines long) strongly keeled, 

 Avith a few minute hairy papilhe : lower palet equalling the u])per glume, copiously 

 hairy on tlie back, its long middle lobe 2-cleft ; central seta longest (aline long); 

 upper palet equalling the lower, with lateral tufts of long liairs at base : pedicel of 

 sterile Horet about a line long, hairy at top and bearing a rudimentary hooded palet 

 and 3 very short awns. — Gray, j\lan. G21. Atlwropoijon oh'ijostachi/um, Nutt. Gen. 

 i. 78. Chonilrosium oh'gostachi/inn, Torr. in Marcy liep. 300. 



Summit of Providence Jlountaiii, Cooper. Tliis sjiecics, wliicli extends horn "Wisconsin west- 

 ward, is common in Nebraska and southwestward to Northern Mexico. The specimens from Dr. 

 Coojier, wlio alone seems to liave met witli it in CaUfornia, are only 6 inches high. 



2. B. polystachya, Torr. Culms 3 to 15 inches long: leaves scabrous, often 

 with a few hairy pa[)ilhe on tlio margins and midnerve ; sheaths loose : spikes 3 to G 

 or n)ore, | to 1 inch long, rarely slightly curveil, the scabrous rhachis hispid-ciliate : 

 spikelets about 2 lines long : glumes often irregularly 2-toothed, the up|)er broadly 

 ovate, a lino long, rough-pubescent, short-awned below the apex : lower palet very 

 hairy on the nerves below, otherwise smooth and shining, the central lobe rather 

 obtusely bilid, the lateral narrow and acute ; lateral sette stoutest and longest ; upper 

 palet equalling the lower, silky-hairy on the margins and on each side at base : im- 

 l)erfect lloret of 2 small (mostly) hoodeil palets and 3 setse, upon a hairy pedicel which 

 also bears a very minute rudimentary third lloret. — Pacif. W. IJej). v. 36G, t. 10. 

 Chnndrosinm ])o/i/sfiic/i>/)im, l>enth. I'ot. Sulph. 5G ; Torr. in Emory Kep. 153. B. 

 pnmila, liuckl. Proc. Acad. I'hil. 18G2, 1)3. 



Fort Mohave {Cooper) ; Colorailo River {A. Schott), and eastward ; very common in the Rio 

 Grande region and southward. Varying from nearly prostrate to erect with very slender culms ; 

 the spikes generally dark purple and the foliage more or less tinged. The seta; of the lower palet 

 also vary considerably in length, and sometimes the imjierfect lloret has a broad cordate palet 

 awned between the lobes, and the second imiicrfect iloiet becomes more conspicuous. 



* * Spikes short, few-flowered, at length reflexed : j^oint of rhachis prolonged. 



3. B. aristidoides. Gidms G t(» 18 iniihes liigh, bniiu^licd above : leaves soon 

 involute, scabrous above, margins with scattered 1-haired jvipilhe ; sheaths very loose, 

 Hmonth (ixcept a haii'y tuft at throat on each side: spikes \ to S, distant, seeund, 

 8 to 10 lines long, on white hairy jiedicels 2 lines long; rhachis scabrous, the tri- 

 quetrous point equalling the terminal spikelet : spikelets 3, distant, appressed, about 

 3 lines long; lower glume almost sctiform, tlie upper subulate, strongly keeled, some- 

 times 3-toothed : perfect floret with a slightly bearded callus ; lower palet coriaceous, 

 silky-pubescent on the nerves, minutely punctulate, nearly equalled by the upper : 

 imperfect llower on a short jiedicel slightly hairy at top, of 3 unecpial awn.s, one 

 3 lines long, the shorter slightly dilated below.- — Dinehra aristidoides, IIBK. Nov. 

 Gen. i. 171, t. G95. Eutriana aristidoides, Kunth, Enum. i. 280, and Suppl. 233. 



Fort Ynma. {^[ajor Tlwmcis) ; San Diego County, Palmrr. Common in Arizona and Mexico. 

 Api)arently monocarpic, the cluster of withered sheaths at the base indicating that it takes a rest 

 and completes its growth the second .season. The young plant, with its spikes erect and appressed, 

 presents a strikingly dilferent appearance from the old one, when its fully developed spikes are 

 refracted. The long awns to the sterile floret give it so strong a resemblance to an Arislida that 

 the specific name is especially descrii)tive. 



29. CYNODON, Riclmnl. Do(j's-tootii Giiass. 

 Inflorescence in several one-sided flattened spikes which are digitate at the end of 

 the peduncle. Siiikelets l-flowered, with a ruiliment consisting of a naked pedicel 



