360 Missouri Agricultural Report. 



classification of the weed seeds found in farm seeds with respect to their 

 relative importance is a desirable feature of popular seed testing. 



The following brief descriptions refer serially to illustrations of 6() 

 kinds of weed seeds shown in figures 19, 20 and 21 : 



Crab-grass seeds (fig. 19, a) usually bear the outer chafif, wliich is ofter» 

 soft-hairy, one scale as long as the seed and distinctly 3-ridged, the other half 

 the length of the seed; straw-colored, brown or _purplish; common in seeds of 

 clovers, alfalfa and grasses; plants sometimes very troublesome. 



Witch-grass seeds (fig. 19, b) occur both with and without the outer chafif, 

 which is lance-shaped, smooth and brown; seeds free from the chafif are oval,, 

 light gray or dark gray, smooth and polished; common in seeds of clovers, 

 alfalfa and grasses; plants widely distributed; comparatively unimportant. 



Yellow foxtail seeds (fig. 19, c) are oval, flat on one side and arched on the 

 other, chaf¥ straw-colored, light brown or greenish, as long as the seed on the 

 flat face, a half-length scale on the arched face; the light-colored or dark-col- 

 ored seed within the chafif distinctly ridged crosswise on the arched face, ofter» 

 free from the outer chaff; common in many kinds of farm seeds. 



Green foxtail seeds (fig. 19, d) are oval, convex on both faces, the whitish 

 or straw-colored outer chafif as long as the seed on both faces; seed within the 

 chaff straw-colored, gray or brown, the darker seeds often mottled, the surface 

 finely roughened and dull; common in many kinds of farm seeds. Both yellow 

 and green foxtail grasses are widely distributed summer weeds, occupying val- 

 uable space in crops. Green foxtail seeds are distinguished from seeds of fox- 

 tail millet by their smaller size and rough, dull surface. 



Velvet grass seeds (fig. 19, e) usually appear in the chafif, which is thin, 

 oval and straw-colored, the surface covered with fine, stiffish hairs; a single 

 oval, shining seed usually found within the chafif; a common impurity of coarse 

 grass seeds. 



Soft chess seeds (fig. 19, f) are lance-shaped, usually much flattened, straw- 

 colored, the lemma awned at its apex, its back usually wrinkled, the palea and 

 grain shorter than the lemma; common in imported coarse grass seeds; widely 

 distributed in the United States, but not an important weed except on the 

 Pacific coast. 



Sedge seeds (fig. 19, g), when covered by the chafify hull, are flask shaped, 

 straw-colored, brown, or greenish, flatteiied and thin with respect to the several 

 kinds found in farm seeds; seeds freed from the outer chafif are oval, lens- 

 shaped, and light brown; common in grass seeds, particularly bluegrass seed; 

 plants comparatively unimportant. 



Sorrel (or sheep's sorrel) seeds (fig. 19, h) are small, oval, 3-angled, the 

 outer chafify hull dull reddish-brown; seeds freed from the hull are reddish- 

 brown, smooth and polished; found in farm seed both with and without the 

 hull; a common impurity, appearing in seeds of clovers, grasses, poorly cleaned 

 cereals, millets, etc.; a cosmopolitan weed often troublesome until subdued. 



Knotweed seeds (fig. 19, i) are sharply oval, 3-angled, dull reddish-brown 

 in the absence of the brown chafify covering, a part of which is usually borne 

 at the broader end; common in clover seed and grass seed; plants usually of 

 minor importance as field weeds. 



Pale knotweed seeds (fig. 19, j) are nearly circular, flattened, and chestnut 

 brown when freed from the reddish-brown, sometimes adherent, chafify cover- 

 ing; common in seed of coarse grasses, cereals and flax, often abundant in 



