446 



WEED FLORA OF IOWA 



arvensis; taste pungent. Generally found in seed of clover and 

 alfalfa. 



Indian Mustard (Brassica juncea). 



Seed about the size of wild mustard seed ; surface rather coarsely 

 reticulated. Color dark reddish brown. 



30-- 



Figure 290 A 



Figure 296B 



Fig. 296. A. Indian Mustard (Brassica juncea). B. Hare's-ear Mustard 

 (.Conringia orientalis) . a, b, different views of seed; c, cross section; d, 

 natural size. * 



(After Hillman, Bull. Mich. Agr. Exp. Sta.) 



Hare's-ear Mustard (Conringia orientalis (L.) Dumort.). 



Pod rigid, 4-angled; seeds brown, oblong narrowed to rounding 

 at the ends, 2-2.5 mm. long; surface finely reticulated in checks; 

 scar at end of seed lighter in color; position of caulicle indicated 

 by two distinct, lengthwise grooves. 



Tumbling Mustard (Sisymbrium altissimum L.). 



Seed oblong flattened, one-twenty-fifth in. in length ; color reddish 

 yellow ; radicle prominent, variable in shape ; form of embryo 

 marked by deeper color, by lines; seed coat becomes mucilaginous 

 when wet. A tumbling weed. Distribution wide, reported as a 

 serious weed in commercial seeds of the northwest and Canada. 



Hedge Mustard (Sisymbrium officinale (L.) Scop.). 



Seed oblong, sometimes with upper end truncate, some almost 

 trapezoidal in outline, one-twenty-fourth to one-sixteenth in. long ; 

 color yellowish, or brownish, variable ; caulicle evident from promi- 

 nent white scar ; funicle sometimes present and pointed ; seed coat 

 mucilaginous. Found in alsike and white clovers. 



