734 IOWA DEPARTMENT OF AGRICULTURE 



OTHER WEED SEEDS COMMONLY FOUND IN FARM SEEDS. 



Certain kinds of weed seeds other than those termed noxious under 

 the preceding heading are found frequently, sometimes abundant, in var- 

 ious kinds of farm seeds, and thus cause inquiry from one examining 

 seeds. The degree of noxiousness of this class of weed seeds differs with 

 the kinds and with the conditions of locality, climate, etc., under which 

 they are sown. While some of the kinds included in the present list are 

 looked upon, at least locally, as pests, many of the kinds mentioned are 

 of little importance as field weeds. Since it is essential to distinguish 

 the relatively unimportant from the important seeds, a fairly accurate 

 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 60 

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



Crab-grass seeds (fig. 19, a) usually bear the outer chaff, which is 

 often 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 

 chaff, which is lance shaped, smooth and brown; seeds freed from the 

 chaff are oval, light gray or dark gray, smooth, and polished; common 

 in seeds of clovers, alfalfa, and grasses; plants widely distributed; com- 

 paratively unimportant. 



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

 on the other, chaff 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-colored seed within the chaff distinctly ridged crosswise 

 on the arched face, often 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 whit- 

 ish or straw-colored outer chaff 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 distrib- 

 uted summer weeds occupying valuable space in crops. Green foxtail 

 seeds are distinguished from seeds of foxtail millet by their smaller size 

 and rough, dull surface. 



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

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

 single oval, shining seed usually found within the chaff; a common im- 

 purity 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 impor- 

 tant weed except on the Pacific coast. 



