358 Missouri Agricultural Report. 



Tumbling mustard seeds (fig. i8, c) are very small, flattened, oblong and 

 yellowish, often with a greenish line along the side; found in clover and flax 

 seed from the Northwest. 



Wild carrot seeds (fig. i8, d) are light brown, oval, flattened, nearly plane 

 on one side and ridged lengthwise on the other, the ridges often bearing the 

 remnants of whitish spines; common in red clover and in imported alfalfa seeds, 

 sometimes found in grass seed. 



Field bindweed seeds (fig. i8, e) are coarse, oval, rounded on one side and 

 angular on the other, gray, owing to numerous light-colored raised spots on 

 the surface; common in seeds of cereals, in flax, and in other coarse seeds. 



Seeds of the dodders (fig. i8, f-j) as as group are recognized by their dull, 

 finely roughened surface, together with their rounded or angular form and 

 their small size. The slender spirally coiled embryo of the seed, devoid of 

 two cotyledons, is characteristic of dodder seed". 



Flax dodder seeds (fig. i8, f) are rounded on one side and angular on the 

 other, many of the seeds united together in pairs; soiled gray in color; found 

 only in flax seed; common in imported seed and in some domestic seed. (See 

 fig. 12.) 



Clover dodder seeds (fig. i8, g) are very small, nearly splierical as a rule, 

 gray or brown; often distinctly pitted; common in imported clover and alfalfa 

 seeds; not found in grass seed. (See figs, i and 2.) 



Small-seeded alfalfa dodder seeds (fig. 18, h) are similar in size to seeds 

 of clover dodder, but are more oval and angular in form; colors yellowish, 

 greenish or purplish; common in alfalfa seeds from the Western States. Of 

 the dodders infesting alfalfa this is the most widely distributed within the 

 United States. Its seed is not found in red clover or grass seeds. 



The seed of clover dodder and small-seeded alfalfa dodder are sufficiently 

 small to admit of being wholly removed from clover or alfalfa seed of good 

 grade by the use of a sieve of proper mesh (about 20 to the inch); Clover 

 dodder is a menace in any part of the country. Small-seeded alfalfa dodder 

 appears to be naturally confined to the dry regions of the West. 



Field dodder seeds (fig. 18, i) are larger than those of clover or small- 

 seeded alfalfa dodder, rounded on one face and flattened and angular on the 

 other; the characteristic seed scar is a more or less distinct, circlilar area, hav- 

 ing a short, raised whitish line in its center; seeds from the Great Basin region 

 ■gray 01: pinkish, those from Chile (evident in Chilean red clover and alfalfa 

 seed) reddish-brown; found in both red clover and alfalfa seed, commonest in 

 western-grown alfalfa seed and in Chilean red clover and alfalfa. The plants 

 are very destructive to clover and alfalfa. 



Large-seeded alfalfa dodder seeds (fig. 18, j), the largest of the dodders 

 found in alfalfa, are variable in size; some are not larger than and are similar 

 to the seeds of field dodder; the largest are nearly circular, rounded and flat- 

 tened; color gray, greenish, or more commonly brown; scar devoid of the 

 •raised whitish line to be seen in field dodder and often indistinct; found only 

 in alfalfa seed produced in the Western States. This dodder does not appear 

 to thrive in the Eastern States. Field dodder and large-seeded alfalfa dodder 

 .are termed large-seeded because their seeds can not be wholly removed from 

 .clover and alfalfa seed. The greater part of the field dodder can be removed 

 "by the use of a sieve of 20 meslies to the inch. 



Corn gromwell seeds (fig. 18, k) are oval, gray or brown, and being very 



.a See Farmers' Bulletin 306, "Dodder in Relation to Farm Seeds." 



