146 UNIVERSITY OF MISSOURI STUDIES [288 



Michigan to British Columbia; Missouri to Texas; Cal- 

 ifornia. 



443. N. sessiliflorum Nutt. IR.sessilifiora {Nutt.)H'nchc.}. 

 Wet grounds and muddy banks, usually in shade. 

 Virginia to Iowa and Kansas; Florida to Texas. 



175. OARDAMINE L. Bitter-cress. 



444. 0. parviflora L. Small bitter-cress. 



Common on rocky banks; apparently intergrades with the 

 next. 



Quebec to Oregon; Georgia to Missouri: Europe and 

 Asia. 



445. O. Pennsylvanica Muhl. Pennsylvania cress. 

 Common along streams and in springy places. 

 Newfoundland to Alaska; Florida to Missouri and 



California. 



446. O. rhomboidea DC. [C. bulbosa (Schreb.) B. S. P.]. 

 Spring cress. 



In rills and springs; local. 



Nova Scotia to Minnesota and South Dakota; Florida 

 to Texas. 



176. DENTARIA L. Toothwort. 



447. D. laciniata Muhl. Pepper-root. 

 Common in rich moist woods. 



Quebec to Minnesota; Florida to Louisiana. 



177. OAPSELLA DC. [BURSA Weber]. Shep- 

 herd's PURSE. 



448. O. Bursa-pastoris (L.) Medic. [B. Btirsa-pastoris 

 (L.) Britton]. 



Very common in fields and waste places. 

 Europe, now cosmopolitan. 



178. DRABA L. Whitlow-grass. 



449. D. cuneifolia Nutt. 



