10 



A comparison of the North Anioricau species oi Elymus of this group with types of 

 pnl>lishecl species or with authentically named material is greatly to he desired, 

 and is iu fact necessary to the jjositive identiiicatiou of the species. 

 Eragrostis obtusiflora Scribn. (Brizopynim obtuslflorum P^oum. ?) (Plate Y.) A 

 rigid, ii'laucoHS perennial, 3 to 5 dm. high, with strong, creeping rootstocks, stiff, 

 pungent-pointed leaves, and more or less spreading panicles 8 to 14 cm. long. 

 Scales of the stout rootstocks clo.sely imbricated Sheaths striate, sparingly 

 pilose at the throat, covering the internodes; ligiile very short, ciliate; leaf 

 blades erect-spreading, about 4 mm. wide at the base, convolute toward the 

 cartilaginous apex, minutely scabrous above, smooth Ijeneath. Panicle-branches 

 erect or somewhat spreading, sharply triangular, minutely scabrous, the lower 

 branches 5 to 7 cm. long. Spikelets 5- to 12-tlowered, 7 to 1.5 mm. long, lan- 

 cecdate, the tlorets rather crowded; empty glumes ovate-acute, somcw'nat coui- 

 pressed, 1-nerved, the smaller, lower one two-thirds the length of the first 

 floret ; flowering glumes broadly ovate, obtuse or subacute, rounded on the hack, 

 strongly 3-nerved, tirm-membranaceous, smooth ; palea broadly 2-keeled, minutely 

 scabrous on the keels, about the length of the glume. 



No. 193 Wright (collection of the Mexican Boundary Survey under Maj. W. 

 H, Emory), on the margins of Laguua de Sta. Maria. Sulphur Springs Valley, 

 Arizona, Prof J. W. Tourney, September 26, 1896. 



Dr. Thurber, in his manuscript notes upon the gras-ses of the Mexican Boundary 

 Survey, doubtfully referred this species to Glyceria, but its distinctly 3-nerved 

 flowering glumes at once separate it from that genus. The habit of growth sug- 

 gests ,1 relationship with Disliclilis and also with Jourea. The nervation of the 

 glumes at once distinguishes it from JUsiithUs, while the character of the inflo- 

 rescence and the hernuiphrodite spikelets clearly sejiarate it from Joiirea. 



"This species is one of the most abuudant grasses in the extreme alkaline por- 

 tions of Sulphur Springs Valley, where the large rootstocks in many ]»laces bind 

 the sliilting sands. It rarely flowers, and its suijerficial appearance, without 

 flowers, is nnich the same as our common salt grass (IHstichJi-s spicala). It is a 

 hard, rigifl grass, but furnishes a large i)art of the forage of Sulphur Sju'iugs Val- 

 ley, when other grasses are eaten off or are cut short by drought." (Professor 

 Touuiey. ) 

 Sporobolus plumbeus (Trin.) Hemsl. (I'late VI). Vilfd jihiinhca Trin., Agrost. 

 1 : 76, not Fourn.) A diffusely branching, leafy perennial 2 to 3 dm. high, with 

 creeping rhizomes and spreading, rather few-flowered panicles 5 to 9 cm. long. 

 Lea\es crowded below. Sheaths loose, somewhat compressed, striate with scari- 

 ous margins; lignle very short, hyaline, decurreut; leaf blades 3 to 7 cm. long, 

 about 2 mm. wide, acute, nunutely scabrous on the margins, especially near the 

 tips, otherwise smooth. Panicle-branches more or less spreading, solitary, 1 to 

 ■5 cm. long, naked below the middle. Spikelets 3 mm. long, ovate, subacute; 

 outer glumes suberjual, rounded obtuse, second one sometimes broadh' trun- 

 cate, nerveless, about half the length of tln^ flowering glume; flowering glume 

 broadly'lanceolate, 3-nerved, subacute or submucronate ]K)inti'd, minutely scab- 

 rous toward the apex; palea somewhat broader than the floral gliiuie, about 

 equaling it in length, minutely scabrous near the tip. Mexico, No. 6617 C. G. 

 Pringle, ISitfi. 



Mr. J'ringle's specimens agree so nearlj^ with Trinius, characters of his Vilfa 

 phiinlxa, that it seems almost certain they belong to that sjiecies. 1 have not, 

 however, been able to compare them with the type specimens. Trinius describes 

 nifa pJiimUftt as haviiig jjanicles 2 inches long, the solitary branches n;iked 

 below from the middle, the spikelets a line long and glabrous, with the leaves 1 

 to 1^ inches long and about a lino wide. In Pringle's sjiecimens the spikelets 

 are 1.} lines long, and both the flowering glume and palea minutely scabrous 

 toward the apex. The leaves are from 1 to 3 inches long. But this difference 



