iowa academy of sciences. 225 



Sisymbrium L. 



276. S. officinale (L.) Scopoli. A common weed, 



naturalized from Europe. 



Brassica L. 



277. B. m'l/ra (L.) Koch. IMack Mustard. Waste places; 



less common than the next. Introduced from 

 Europe. 

 •278. Ji. arrensi.s (L.) B. S. 1*. (B.' siiiapist rum Boiss.) 

 Charlock. Introduced from Europe into grain 

 fields, where it is very common and troublesome. 



Roripa Scop. 



279. li. pahi.sffis (L.) P.ess. {Nastartiion paliistre D C.) 



Common in low fields and swamps; the pods 

 variable in shape. 



280. B. arinoracia (L.) A, S. Hitchcock. ^Nasturtium 



arnigracia Fries.) Horse-radish. An occasional 

 escape from cultivation; a native of Europe. 

 Cardamine L. 



281. C. parriflora L. (C Jnr.suta var. si/Irafica Gray.) 



Frequent in woods, Iowa Lake. 



282. C. bulbosa (Schreb.) B. S. P. (C. rhomhoidea 



D C.) Frequent along w^ater courses. 

 Dentaria L. 



283. D. laciniata Muhl. Pepper-root. Frequent in 



rich woods. 

 Bursa Webber. Shepherds' Purse. 



284. B. hursa-pastoris (L.) Britton. (Capsella hursa- 



pdsturis Medic.) Naturalized from Europe; 

 very common. 

 Camelina Crantz. 



285. C. sutira (L.) Crantz. False Flax. Adventive 



from Europe in flax fields. 

 Sophia Adans. 

 285. S. pinHcita (Walt.) Britton. (Sisi/nihriuin canes- 



ccfis Nutt.) Bare on dry prairies. 

 Arabis L. 



287. .1. dentata Torr. & Gray. Rare in woods, Iowa Lake, 



288. A. I/ir.sHf(( (L.) Scop. Rare in woods, Estherville. 



15 



