SEEDS OF QUACK-GKASS AND OF CEETAIN WHEAT-GRASSES. 



\V. 



Fig. 4.— Splkelets of quack-grass, showing different forms. Note the 

 forms of the ghimes in o, 6, c, d, and the awned fonn of glumes and 

 seeds shown in d; e, edge view of spikelet. (Enlarged.) 



along with the comparatively few individual seeds in samples of 

 brome-grass seed containing seeds of quack-grass. 



SLENDER WHEAT-GRASS (aGROPYRON TENERUM, VASEY). 



The spikclets of slender wheat-grass (fig. 6) vary from one-half to 

 three-fourths of an inch in length and contain four to seven seeds. 

 Both glumes and seeds may be slenderly acute or short awned 

 at the apex. The 

 glumes may diverge 

 somewhat in mature 

 spikelets, but they 

 are commonly nearly 

 parallel and curved 

 at the back, the tips 

 curving inwardly 

 over the seeds, which 

 exceed the glumes 

 scarcely at all or by 

 as much as one-third 

 the length of the glume. The spikelets usually taper from the 

 center to both ends both facewise and edgewise, the two faces being 

 une([ually convex, the glumes being more widelv separated on the 

 more convex face. (See fig. 6, c, d, and e. ) The spikelets are generally 

 narrower than those of quack-grass, the base being smaller as a rule. 



The glumes (see fig. 6) are relatively 

 broader than those of quack-grass, five 

 veined to seven vemed, the veins 

 slender and distinct, the middle or keel 

 vein scarcely coarser than the adjacent 

 ones, and the glume rounded at the 

 back rather than keeled or angled. 

 The thin, pa[)ery margins of the glumes 

 narrow gradually to the tapering or 

 awned apex. 



]\hiture spikelets of slender wheat- 

 grass tend to break apart readily, only occasional complete spike- 

 lets appearing in commercial samples of seed. Empty glumes 

 (see fig. 6, a) often remain united and appear both free from and 

 attached to a part of the seed-cluster axis. As an impurit}' of 

 brome-grass seed, slender wheat-grass, therefore, usualh' a])pears as 

 free seed, with occasional spikelets or glumes to be depended upon 

 for identification, 

 [Cir. 7y] 



Fig. 5.— Empty glumes of quack-grass spike 

 lets, showing common forms. (Enlarged.) 



