152 



Fig. 146. CAI.AMAGROSTIS TWEEDYI Scribn. in Vasey. Contr. U. S. 

 Nat. Herb. 3 : 83. 1892. (Deyeuxia tweedyi Scribn. Bui. Torr. Bot. Club, 10 : 04. 

 1883. )-A .stout perennial 7-10 dm. (2i°-3i°) high, with rather broad, flat leaves 

 and densely flowered spike-like panicles 8 to 12 cm. (3'-5') long. Sheaths loose, 

 striate, smooth; ligule 2-4 mm. (l"-2") long, decurrent; leaf-blades flat, 6-10 

 mm. (3"-5") broad, 15-20 cm. (6'-8') long, those of the culm shorter. Spikelets 

 5-6 mm. (2i"-3") long with lanceolate, acute, empty glumes (a) which are sca- 

 brous on the back and a little longer than theawned flowering glume (b) ; awn 

 stout, inserted below the middle and about 6 mm. (3") long. Callus hairs few, 

 about 1 mm. {i") long.— Cascade Mountains, Washington. 



A unique species with no near ally, remarkable for its robust culms, broad 

 leaves, and dense panicles. 



