730 IOWA DEPARTMENT OF AGRICULTURE 



Bladder campion seeds (fig. 17, k) are brown or nearly black, flattened, 

 finely tubercled, the tubercles arranged in more or less distinct rows on 

 the sides and in more distinct rows on the edges; occurs, frequently in 

 imported grass seed and is sometimes abundant in seed of red and alsike 

 clovers grown in the Northern States and in Canada. 



Night-flowering catchfly seeds (fig. 17, 1) are similar to the preceding 

 dark gray or brown, finely tubercled, the tubercles not in distinct rows 

 on the sides; very common and often abundant in seed of red and alsike 

 clovers grown in the Northern States and in Canada. Careful compari- 

 son of seeds with the illustrations (fig. 17, j, k and 1; fig. 19, t) will en- 

 able one to distinguish the similar seeds of this group of weeds. Fig. 

 19, t, shows the seed of the forked catchfly, which is common in low- 

 grade European red clover and alfalfa seed. 



The seeds of cow cockle (fig. 17, m) are almost perfectly spherical, 

 black, the surface covered with fine tubercular points; very common in 

 seeds of cereals from the West and Northwest; also in millet and flax 

 seeds, sometimes in imported coarse seeds; broken seeds often occur 

 in alfalfa seed from the Western States, thus indicating its sources. 



Pennycress (or Frenchweed) seeds (fig. 17, n) are oval, flattened, 

 brown, and have concentric ridges on the sides; often found in both do- 

 mestic and imported seed of cereals, clovers, millets and flax. This is a 

 dreaded weed in the Northwestern States. 



Field peppergrass seeds (fig. 17, o) are reddish brown, oval, smooth, 

 and show a curved line on each side; common in domestic and imported 

 seed of various clovers, grasses, and cereals. 



False flax seeds (fig. 17, p and q) as found in farm seeds represent two 

 kinds of false flax (plants in no way related to the true flax). Seeds of 

 the large-fruited false flax (fig. 17, p) are light yellow and much larger 

 than those of the other kind; very common in flax seed (hence the com- 

 mon name); also, in millet and sometimes in alfalfa seed; common in 

 coarse farm seeds from Russia. Seeds of small-fruited false flax (fig. 

 17, q) are much smaller than the others, and darker, being reddish yel- 

 low; common in Canadian red and alsike clovers and timothy seed. 



Ball mustard seeds (fig. 17, r) are unopened, straw-colored, brown or 

 purplish pods, having a network of ridges over the surface and containing 

 a single yellowish seed within: found in seed of cereals, millets, and 

 flax; sometimes in imported seed. This is a troublesome weed in certain 

 sections of the Northern States. 



Black mustard seeds (fig. 17, s) are small, commonly somewhat 

 oblong, and reddish brown or dark brown, sometimes gray, surface pitted, 

 due to a network of ridges; taste distinctly pungent; sometimes found 

 in clover and grass seeds. 



English charlock, or wild mustard, seeds (fig. 17, t) are almost spheri- 

 cal, slightly variable in size, black, reddish brown, or sometimes light 

 brown, the surface comparatively smooth, which distinguishes this seed 

 from seed of other mustards and rape; taste somewhat pungent; a fre- 

 quent impurity of nearly all the common clover grass, and cereal seeds; 

 sometimes an adulterant of rape seed. 



