8 SEEDS OF QUACK-GRASS AKD OF CERTAIN WHEAT-GRASSES. 



WESTERN WHEAT-GRASS (aGROPYROX OCCIDENT ALE, SCRIBX.). 



Well-developed spikelets of western wheat-grass (see fig. 7, a) are 

 larger than those of either quack-grass or slender wheat-grass, often 

 equalmg an inch in length, but are commonly between five-eighths 

 and three-fourths of an inch in length, lance shaped and compressed 



facewise. The slender 

 " glumes are more or less 



divergent, exposing the 

 lower seeds. In the larger 

 spikelets the seeds ex- 

 ceed the glumes equal to 

 the length of the latter, 

 making the larger spike- 

 lets twice as long as the 

 glumes. The seeds are 

 narrowly acute or awn 

 pomted at the apex. 

 The glumes (see fig. 7) 

 are stifnsh, narrowly lance shaped, and a^\^l pointed, three vemed 

 or five veined, the middle vein somewhat coarser than the others, 

 giving the glumes a slightly keeled form, the veins distinct or often 

 obscure. The margins of the glumes are thin and papery, chiefly 

 below the middle, and taper gradually to the pointed apex. 



.I""-.; 



J -I 



d 



>v\^> 



v^. 



Fig. 6.— Emptygliimes(f;)and spikelets of slender wheat-grass. 

 Note the fonns of the glumes: c, d, Opposite sides of a spikelet, 

 showing the relative position of the glumes, d being the inner, 

 more convex side; e, edge view. (Enlarged.) 



Fig. 7.— Spikelets and glumes of western wheat-grass: a, One of the larger spikelets having the maxl- 

 mum number of seeds; 6 and d, small spikelets havmg few seeds; c, edge view of a spikelet; c, free, 

 empty gliraies; /, empty glumes attached to a portion of the cluster axis. Note the form of the glumes. 

 (Enlarged.) 



Mature spikelets of western wheat-grass break apart readily, the 

 seeds separating from the glumes. Snmples of commercial seed, 

 such as brome-grass seed, containing seed of western wheat-grass 

 have few empty glumes (fig. 7, e), some of wliich may remain 

 attached to the spikelet axis (fig. 7, /). 



[Cii-. 73] 



