167 



Fig. 135. Sitanion glabrum J. G. Smith. ORCHARD BARLEY.— a, A group 

 of spikelets; b, one of the florets. Another species of the genus Sitanion is illus- 

 trated by fig. 624 in Bui. 17. 



135. SITANION Rafin. Journ. Phys. 89 : 103. 1819. (.Egilops Nutt,, 1818, not 

 Linn., 1737.) Spikelets usually 2, sometimes 3, or rarely only 1, at each joint of 

 the articulate rachis of the spike, 2- to several-flowered. Empty glumes many- 

 parted from near the base or merely bifid or subulate and entire, a 3d setaceous 

 empty glume above the 2 outer ones is sometimes present, all awned; flowering 

 glumes terminating in a single long awn, or trifid, and 3-awned. Palea as long 

 as its glume, entire, bidentate or 2-awned. Stamens, pistil, and grain as in 

 Elymus, from which genus Sitanion differs chiefly in its divided glumes and 

 in the readiness with which the axis of the spike breaks up, in which latter 

 character it resembles Hordeum. Ceespitose perennials, with usually flat leaves 

 and bearded spikes. 



Species about 25, in Western North America and Mexico. 



