470 



• 



WEED FLORA OP IOWA 



• t 



c 



Figure 337A Figure 337B 



Pig. 337. A. Catnip (Nepeia cataria'). A, views of vartous seeds (nutlets), 

 tliree showing the scar-marldng. B, one having the nutlet wall partially 

 broken away, exposing the seed proper. C, a nutlet in longltudiiial section, 

 showing the embryo. D, group showing the natural size. 

 B. American Germander (.Teucrium canadenae). 

 (A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; B, drawn by L. R. Collins. ) 



Horehiotmd (Marrubium vulgar e L.). 



Seed ovate, one side convex, flattened side divided into 2 faces 

 by strong, central ridge ; one-twelfth of an inch in length ; brownish 



Figure 338A 



Figure 338B 



Fio. 338. A. Giant Hyssop (.Agastache scropTmlariaefoUa'). 



B. Common Horehoimd (.MarruMum vulgare) ; a, angled face; !>, convex face; 



c, longitudinal section ; d, transverse section ; e, natural size of seed. 



(A, drawing by L. R. Collins; B, after Hillman, Mich. Agr. ESxp. Sta.) 



or blackish, with straw-colored markings; scar inconspicnous, in a 

 slight depression somewhat paler in color than seed. 



SeM-heal {Prwnella vulgaris L.). 



Nutlets ovoid, faces convex, marked by longitudinal grooves; 

 one-twelfth of an inch in length; smooth, shining; color brown; 

 small bud marked by white sear appendage. Found in red clover. 



Motherwort {Leonurus cardiaca L.). 



Nutlets 3-sided, occasionally flattened, 1.10 in. long, smooth ex- 

 cept upper end, which is papillose ; minutely roughened ; straw- 

 colored to brownish. Pound in cultivated grass seed. 



