89 



In pairs, densely flowered nearly or quite to the base Empty 

 glumes lanceolate, pale straw-colored and sometimes tmged with 

 purple, the upper 3-nerved, mucronate and often 3-toothed at the 



i 



one-nerved 



lower glume. Flowering glume 2 lines long, pilose below on the 

 back, and for nearly | its length on the margins, termmatmg m a 

 slender awn 6-10 lines long; palea nearly as long as its glume and 

 similarly pilose. Stamens li line long, pale purple. _ 



This species resembles M. gracilis, Tnn., in habit, but is dis- 

 tinguished at once by its very long involute leaves and light colored, 

 more loosely flowered panicle. 



Summits of the Santa Rita Mts., Arizona. _ 



• This is a Mexican grass, not before observed m the distributed 

 collections made within the limits of the United States, and pern^ps 

 now found for the first time within our limits. It should be added 

 that identification of Pringle's specimens with M. virescens, 1 rm., is 

 based upon descriptions of that plant only. _ ^, , t, 



Z2>. * Muhlenbergia debilis, Trin., Agrost., u., 49; Thurber, Bot. 

 Cal., ii., p. 277; M. purpurea, Nutt., PL, 180. 



Foot-hills, Santa Catalina Mts. April, _ 



34. Muhlenber^ia sylvaiica, Torr., var. Pringhi (vel «. sp^— 



Culms densely caespitose, terete, erect, simple, rather rigid, about 



I foot high. Leaves involute, filiform, about 7 to each culm, mm- 



utely scabrous outside, especially towards the tip, strigose scabrous 



within, 4-6 inches long, the lower ones shorter ; ligule broader than 



continued on each side into two lanceolate, acute teeth or auricles 

 one line long. Panicle slender, contracted, 2-3 inches long rather 

 densely flowered. Empty glumes nearly equal, i-nerved, with 

 slender acuminate points, i line long. Flowering glume nearly or 

 quite smooth at the base, 3-nerved, scabrous on the keel above, ii-2 

 lines long, terminating in a slender awn 4-6 lines long ; palea nearly 



equalling its glume. / o \ 



Dry Cliffs, Santa Rita Mts.; alt. 7,000 feet. July (480.) 

 The specimens are not mature, but are developed sufficiently to 

 show the above-enumerated character. Later, the panicle, the base 

 of which is enclosed in the upper sheaths, may become exserted, 

 and the culms, though now strictly simple, may become branched. 

 It is referred to M. sylvatica because of the resemblance of the pan- 

 icle and minute characters of the spikelets to that species. It is 

 distinct from No. 731 of C. Wright's Texan coll called M. monti- 

 cola by Buckley, and referred to M. sylvatica by Munro. 



Girard College, Philadelphia. F. Lamsox Scrtbner. 



The Brittle Branches of Sallx were recently referred to by Mr. 

 Thomas Meehan. Ordinary wood-cells are long, and possess tar>er- 

 ing extremities which overlap each other. This overlapping occurs 

 all along the wood, about as much in one place as m another. In 

 brittle wilows the cells mostly end abruptly at the place where he 

 branch snaps off. At first thought, this might ff f '^^^^f^^^^f- ^.ff ^^^^^J,"^ 

 the structure of the plant. Notwithstanding this peculiarity, such 



