ACJKOSTIDE.E. 255 



A smooth slender bninching geniculate perennial, 10-40 cm, 

 high, the internodes about 2 cm. long. Slieaths mostly shorter 

 than the internodes; ligule 1 mm. or less in length; blade involute, 

 obtuse, 1-3 cm. long. Peduncle slender, 10-15 cm. long, bearing an 

 open ovoid panicle 3 cm. long. Empty glumes equal, 1-nerved, 

 '2.')-o mm. long; floral glume 3 mm. long, 3-nerved, the awn 8-14 

 mm. long. 



Wet ledges. 



Mexico (Jalisco), Pringle 473G. 



32. M. argentea Vasey, Bull. Torr. Club, 13: 232 (1886). 



A slender glaucous ascending perennial, 40-60 cm. high. 

 Leaves of sterile shoots few and stout, short; sheaths of the culm- 

 leaves about 6, longer than the internodes; ligule lanceolate, 8-10 

 nun. long; blade nearly smooth, loosely involute, 8-1:^ cm. long, 

 l..")--2 mm. wide. Panicle narrow or spreading (?) i)artly included, 

 12-18 cm. long, rays single or in twos, capillary, branching, the 

 longest 5-7 cm. long, thinly flower-bearing for most of their length. 

 Spikelets on pedicels 3-8 mm. long, light, silvery green or tinged 

 with red; empty glumes subeqnal, linear-lanceolate, the apex more 

 or less irregularly 2-toothed, 1-nerved, 2.5-3 mm. long; floral 

 glume broadly linear, thinly pubescent on the lower half, 3 mm. 

 long, 3-nerved, with two broad teeth at the apex, the awn 6-15 

 mm. long; palea oval, obtuse, nearly as long as its glume. 



Mexico, Palmer 160. 



33. M. tenuiflora (Willd.) B. S. P. Prel. Cat. N. Y. 67 (1888). 

 A(j)'ostis tenuiflora Wild. Sp. PI. 1: 364 (1798). Cimia tenuiflora 

 Link, Enum. 1:71 (1821). JIuhlenhergia WilldenoviiTvm.Jjm^. 

 188 (1824). 



Culms upright, rather slender, simple or only sjiaringly branched, 

 65-90 cm. high, from scaly creeping rootstocks. Sheaths scabrous ; 

 ligule about 1 mm. long; blades flat, thin, pungent-pointed, sca- 

 brid, 10-14 cm. long, 4-7 mm. wide. Panicle very slender, loosely 

 flowered, 20-40 cm. long, rays distant, mostly in pairs, the longest 

 8-10 cm. long, slender. Spikelets on pedicels, the shortest of which 

 are 1-2 cm. long, empty glumes subeqnal, ovate, short-i)ointed, 1- 

 nerved, about 2 mm. long; floral glume ovate-lanceolate, 3-nerved, 



