130 UNIVERSITY OF MISSOURI STUDIES [278 



I9OV2. ARMORACIA Gaertn. Horse radish. 



473. A. Armoracia (L.) Cockerell. Nov. comb. [Roripa Armo- 

 racia (L.) A. S. Hitchc. ; Nasturtium Armoracia (L.) 

 Fries.]. Common horse radish. 



Escaped to waysides, Boulder (Daniels). 

 Europe, thence to America. 



191. SISYMBRIUM L. Hedge mustard. 



474. S. officinale (L.) Scop. Common hedge mustard. 

 Common in viraste places about Boulder, 5100-6000 ft. (Dan- 

 iels, 256). 



Europe and Asia, thence to North America. 



192. SOPHIA Adans. Tansy mustard. 



475. S. leptophylla Rydb. Fine-leaved tansy mustard. 

 Along Boulder Canon, 6000 ft. (Daniels, 284). 

 Wyoming and Idaho to Colorado. 



476. S. incisa (Engelm.) Greene [Sisymbrium incisum 

 Engelm. ; Descurainia incisa (Engelm.) Britton]. Cut- 

 leaved tansy mustard. 



Boulder Canon at Falls ; also in Gregory Caiion on rocky 

 banks, 6000-9000 ft. (Daniels, 981). 

 Wyoming to New Mexico. 



477. S. intermedia Rydb. Western tansy mustard. 

 Common -throughout the lower elevations, 5100-9000 ft. 



(Daniels, 121). 



Michigan to British Columbia; Tennessee to Califor- 

 nia. 



478. S. andrenarum Cockerell. Hoary tansy mustard. 

 Rather frequent in Boulder Canon, 5500-7000 ft. (Daniels, 



550)- 



Montana to Washington and New Mexico. 



193. ERYSIMUM L. Treacle mustard. 



479. E. asperum (Nutt.) DC. Western wallflower. 

 Mountains between Sunshine and Ward (Rydberg). 

 Saskatchewan to Arkansas and Colorado. 



