88 



A. bromoideSy HBK. Thurber, Bot. Cal., ii., p. 298. 

 Mesas, near Camp Lowell. (470.) 

 A very variable species, of which there are two forms in the col- 

 lection ; one with upright culms about 7 inches high, with the 

 branches of the panicle short and erect ; the other with more or less 

 geniculate culms, 18 inches high, with the panicle more open (the 

 lower branches being from 2-^^ inches long and more or less spreading) 

 resembling in habit A. caerulescens, Desf. The first form is the 

 more common in collections from the West, and is that described by 

 Dr. Thurber in Bot. Cal., ii., p. 289, under the name of A. bromoides^ 

 HBK. The different forms of this species, of which the A^ brotnoides^ 

 HBK., is one, were all united by Trinius & Ruprecht under their 

 A. dispersa, Genl. Munro, in his catalogue of the grasses in the 

 herbarium of Linnaeus, says that Aristida Americana,^ L., from Ja- 

 maica, '' is called A. dispersa by Trinius; but Linnaeus's name ought 

 to take precedence. Kunth has misplaced the Linnaean synonym in 

 EutrianajuncifoUar Grisebach, in Flora of the British West Indies, 

 unites A, Af?iericana^ L., A. dispersa^ Trin., A. bromoides^ humilis and 

 coarctata, HBK., and A. cognata^ Trin., under A, stricta^ Michaux. 



27. "^Aristida Hitmboldtiana^ Trin. & Rupr., Stipac, p. 118; Vasey, 

 Bot. Wheeler Exped., p. 286; A. divaricata, HBK. 



Mesas, near Camp Lowell. June. 



28. Stipa occidentalis (?) Thurber, Bot. Wilkes's Exped., p. 483; 

 Bot. Cal., ii., p. 285. 



Mt. Shasta, CaUfornia; alt. 7,000 feet. August. Pringle's speci- 

 mens differ from the description of this species in Bot. Calif., and 

 from specimens in herb., in their more- slender and wiry habit, ex- 

 tremely short ligule, both empty glumes 3-nerved, smaller, shorter 

 and less hairy flowering glume, and the proportionately shorter pale. 

 It seems to be a form intermediate between S. occidentalis and S. 

 Sibirica^ Lam. It differs from the latter species in its narrow 

 leaves, and more plumose and twice geniculate awn.. It appears to 

 be nearer S. occidentalism and may be, as Dr. Vasey suggests, a de- 

 pauperate form of that species. 



29. Muhlenbergia comata, Benth, Vaseya comata^ Thurb., Proc. 

 Phil. Acad., 1863, p. 79; Bot. Cal., 11., p. 278. 



Mt. Shasta, California; alt. 6,000 feet. August. 



30. il//////^/^^-?/-^/^ 7>jv^//^, Thurber, Gram. Mex. Bound., ined.; 

 Porter and Coulter, Synop. Flor. Col., p. 144. 



Mesas and foot-hills, near Tucson. 



31. Muhlenbergia distichopJiylla, Kth., Enum. PI. i., p. 202; Vasey, 

 in Bot. Wheeler's Exped., p. 283; Podosaemiim distichop/iyllum, PresL, 

 in Rel. Haenk., i., 231. 



Canons, Santa Catalina Mts. May. * 



32. "^Muhlenbergia virescens, Trin., Unifl,, 193; Kunth, Enum., 

 PL, i.,202., etSuppL, 160; /^^^/d?^^;^;//////2 virescens.Yi^^,^ Nov. Gen., 

 1., 132; Trichochloa virescens, R. & S., Syst., ii., 389. 



Culms slender, 2 feet high, simple or branched at the base, 

 smooth. Leaves narrow and involute, the upper about^ one foot 

 long, nearly equalling or slightly exceeding the culm. Ligule 6 lines 

 long. ]>anicle 6 inches long, the erect branches single, or the lower 



