736 IOWA DEPARTMENT OF AGRICULTURE 



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

 the outer chaffy 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 chaffy 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, 

 chaffy covering; common in seed of coarse grasses, cereals, and flax, often 

 abundant in imported seed. The plants grow chiefly in moist places and 

 are not troublesome on uplands. 



Lady's-thumb seeds (fig. 19, k) are usually free from the chaffy cov- 

 ering and are then black, shining, broadly oval, and flattened, or some- 

 times 3-angled ; common in various kinds of farm seeds, particularly Amer- 

 ican-grown red clover seed. The habit of the plant is similar to that of 

 the preceding knotweeds, to which it is closely related. This plant is 

 common on dry uplands. 



Larnb's-quarters (goosefoot) seeds (fig. 19, 1) are small, lens shaped, 

 dark brown, or black and shining, sometimes found within a chaffy cov- 

 ering of five scales; common in all kinds of farm seeds, particularly clover 

 and grass seeds; a well-known weed of gardens, cultivated fields, and 

 meadows. 



Wild saltbush seeds (fig. 19, m) are thin, triangular or wedge shaped, 

 veined, straw colored, or purplish, their two scales inclosing a single 

 small seed; found in American-grown alfalfa, not appearing in imported 

 seed. 



Amaranth (pigweed) seeds (fig. 19, n and o) are lens shaped, black, 

 and highly polished. Seeds of rough amaranth (fig. 19, n) are oval in 

 outline; those of tumbling amaranth are somewhat smaller and nearly 

 circular in outline, while seeds of spreading amaranth (fig. 19, o) are 

 much larger and nearly circular in outline, the sides being strongly con- 

 vex. Seeds of rough amaranth and of tumbling amaranth are common in 

 various kinds of farm seeds, particularly clover. Spreading amaranth is 

 native in the Western States and its seeds often appear in alfalfa from 

 that region. 



Wild spurry seeds (fig. 19, p) are very small, black, and nearly spheri- 

 cal. A narrow light-colored rim encircles the seed and serves to distin- 

 guish it from other weed seeds. Some seeds are flecked with whitish par- 

 ticles; common in imported clover seed. 



Chickweed seeds (fig. 19, q and r) are small, mostly brown, nearly 

 circular, and flattened; one kind (fig. 19, q) common in clover seed im- 

 ported from Europe, has numerous interlacing wrinkles covering the sur- 

 face, the other kind (fig. 19, r) is borne by a common weed in lawns, 

 gardens, and thin meadows, has the surface covered with individual tu- 



