AVENE.E. 365 



simple, ovoid or irregularly oblong, 2-3-10 mm. long. Spikelets 2- 

 flowereJ, brown above, red or purple below ; empty glumes nearly 

 equal, about 2.5 mm. long, first 1-nerved, second 3-nerved, the 

 lateral nerves obscure; florets 2.5 mm. long, overlapping for four- 

 fifths of their length, very sparingly clothed at the base with short 

 weak hairs, rachilla smooth, rudiment above the second tiower 

 twice as long as the joint of racliilla between the florets, bearing a 

 small glume or rarely a third floret; floral glume broadly oval, 

 truncate, irregularly toothed, thinner than the emjjty glume, deli- 

 cately 5-nerved; a straight awn a little below the middle, scarcely 

 reaching to the tip of its glume; palca broad, not keeled, a little 

 shorter than its glume, irregularly 4- toothed; the two obscure nerves 

 diverging. Perlnqjs this should be included in D. ccespifosa Beauv. 

 Grinnell Land, Lieut. Greely in 1882; Colorado, Parry 367; 

 Alaska, Harrington, Datl. 



2. D. Pringlei Scribn. Proc. Acad. Phila. 300 (1891). 



Culms erect, panicle simple, 60-90 cm. high. Sheaths scabrid, 

 smooth, shorter than the internodes, oblique at the throat; ligule 

 truncate, fringed, decurrent, about 2 mm. long; blades scabrous, 

 involute, rigid, 10-15 cm. long, 2—4 mm. wide. Panicle dense, 

 spikelike, somewhat interrupted below, 7-17 cm. long, the lowest 

 rays branching, spikelike, appressed, 2-5 cm. long. Spikelets linear- 

 lanceolate; empty glumes equal, 4.3-5.3 mm. long, 1-nerved, keel 

 scabrous, joint of rachilla between florets about 0.3 mm. long; 

 floral glume linear, about 3-4 mm. long, with 2 blunt lobes, awn 

 one-third the way from the base and projecting above its glume 3-4 

 mm. ; palea thin, 2-keeled, 2-toothed, a little shorter than its glume- 

 Anthers linear, 1.2 mm. long. 



This has much the aspect of Trisetum. 



Mexico, Pringle 1429. 



3. D. flexuosa (L.) Trin. Bull. Sci. Acad. St. Petersb. 1:66 

 (1836). Aira flexuosa L. Sp. PI. 65 (1753). There are many 

 other synonyms. 



A tufted perennial, 40-60 cm. high, culms nearly naked. Lig- 

 ule short; blades very narrow, those at the base 3-12 cm. long, 

 those of the culm 2-5 cm. long. Panicle spreading, 8-12 cm, long. 



