A SEED KEY TO COMMON WEEDS 349 



somewhat four-angled, shorter and broader than Verbi na 

 hastata. 0.. common along roadsides and found as an adulter- 

 ant of red clover. Native. 



69. Verbena hast at a L. Blue Vervain. L.. 1.7 — 2-4 mm. 



W., .4 — .7 mm. C. dull reddish brown. S., oblong to cylin- 

 drical : one side very convex and with about five narrow longi- 

 tudinal ridges, the other side made up of two plane faces set 

 at an angle of about 40 degrees and with a white scar at one 

 end; shorter and broader than Verbena urticaefolmm. 0., com- 

 mon in some clovers. Native. 



70. Nepeta Cataria L. Catnip. Cat Mint. L.. 1.3 — 1.7 mm. 

 W., .8 — 1.2 mm. C. and S., dull red with two oval-shaped 

 white cavities placed end to end near one end of the seed, the cav- 

 ities being filled with a white cottony substance ; broadly oval 

 and slightly compressed. 0.. very abundant but not danger- 

 ously common in clover seeds. Introduced from Europe. 



71. Prunella vulgaris L. Self Heal. Heal All. Carpenter 

 Weed. L.. 2. — 2.6 mm. W., .9 — 1.2 mm. C. shining light or 

 dark brown. S.. slightly flattened oval tapering at one end 

 to a small triangular whitish appendage ; with two dark longi- 

 tudinal lines on each side. 0.. one of the commonest impuri- 

 ties of clover, alfalfa and grass seeds. Introduced near Wash- 

 ington from Europe. 



72. Leonurus Cardiaca h. Common Motherwort. L.. 2. — 

 2.5 mm. AY.. .8 — 1.2 mm. C. light or dark brown. S.. one 

 side rounded, two sides plane with the apex of the seed broader 

 than the base. 0.. common in waste places. Introduced from 

 Europe. 



73. Datura Stramonium L. Stramonium, Jimson-weed. 

 Thrrn Apple. L.. 3.-3.8 mm. AY.. 1.7—2.2 mm. C. dark 

 brown. S.. flattened oval with irregular elevations and pits ; 

 one edge nearly straight, the rest curved. 0.. found quite com- 

 r. mly in waste places: poisonous. Introduced from Asia. 



71. Verbascum Thapsus L. Common Alullein. L.. .5 — 1. 



n m. AY.. .4 — .7 mm. C. usually dark brown, sometimes light. 



somewhat cylindrical but of a slightly smaller diameter at 



the apical end: surface covered with oval grooves or pits. ""The 



p'.:um; surface seems to predominate in Verbascum Blattaria 



