Cijnodou. GRAMINE.E. 291 



* Sjnkes pectinateUj many-flowered, erect or spreading, the rhachls not xrrolonged 

 beyond the spikelets. 



1. B. oligOStachya, Torr. Perennial, G to 18 inches higli : leaves smooth or 

 barely roughened above: spikes 1 to 5, remote, 1 to 1|- inches long, often much 

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

 (including sette) about 3 lines long : glumes (the upper 2 lines long) strongly keeled, 

 with a few minute hairy papillaa : lower palet equalling the upper glume, copiously 

 hairy on the back, its long middle lobe 2-cleft ; central seta longest (a line long) ; 

 upper palet equalling the lower, with lateral tufts of long hairs 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, Man. 621. Atheropogon oligostachyum, Nutt. Gen. 

 i. 78. Chondrodum oligostachyum, Torr. in Marcy Rep. 300. 



Summit of Providence Mountain, Cooper. This species, which extends from Wisconsin west- 

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

 Cooper, who alone seems to have met with it in California, are only 6 inches high. 



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

 with a few hairy papilhe on the margins and midnerve ; sheaths loose : spikes 3 to 6 

 or more, | to 1 inch long, rarely slightly curved, the scabrous rhachis hispid-ciliate : 

 spikelets about 2 lines long : glumes often irregularly 2-toothed, the upper broadly . 

 ovate, a line 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 bifid, the lateral narrow and acute ; lateral setae stoutest and longest ; upper 

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

 perfect tloret of 2 small (mostly) hooded palets and 3 seta?, upon a hairy pedicel which 

 also bears a very minute rudimentary third iloret. — Pacif. E. Rep. v. 366, t. 10. 

 Chondrosium polystachyum, Benth. Bot. Sulph. 56; Torr. in Emory Rep. 153. B. 

 pumila, Buckl. Proc. Acad. Phil. 1862, 93. 



Fort Mohave {Cooper) ; Colorado River {A. Schott), and eastward ; very common in the \\'\o 

 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 imperfect floret has a broad cordate palet 

 awned between the lobes, and the second imperfect Horet becomes more consjjicuous. 



% % Sjyikes short, fetv-floivered, at length reflexed : j^oint of rhachis prolonged. 



3. B. aristidoides. Culms 6 to 18 inches high, branched above: leaves soon 

 invt)lute, scabrous above, margins with scattered 1-haired papillte ; sheaths very loose, 

 smooth except a hairy tuft at tin-oat on each side : spikes 4 to 8, distant, secund, 

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

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

 3 lines long; lower glume almost setiform, the 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 flower on a short pedicel slightly hairy at top, of 3 unequal awns, one 

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

 Gen. i. 171, t. 695. Eutriana aristidoides, Kunth, Enum. i. 280, and Supph 233. 



Fort Yuma {Major Thomas) ; San Diego County, Palmer. Common in Arizona and Mexico. 

 Apparently 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 sjjikes erect and appressed, 

 presents a strikingly different appearance from the old one, when its fully developed si)ikes are 

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

 the specific name is esjjecially descriptive. 



29. CYNODON, Richard. Dog's-tooth Grass. 



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



the peduncle, Si)ikelets 1-flowered, with a rudiment consisting of a naked pedicel 



