1874.] 75 [Allen. 



Yellowstone. Varies in height from a few inches to three feet, ac- 

 cording to locality. 



55. [Crataegus COCCinea Linn.] Occasional along the banks 

 of the streams. 



56. Amelanchier Canadensis T. and G. Heart Kiver 

 Crossing, June 25th. Widely dispersed, but not common anywhere. 



ONAGRACE^L 



57. Epilobium paniculatum Nutt. Bad Route Creek, 

 July 28th. 



58. Gaura COCCinea Nutt. Heart River, July 6th. 



59. CEnothera biennis Linn. Bad Route Creek, July 28th 

 59a. CEnothera biennis Linn., var. Head of Heart River, 



July 8 th. 



60. CEnothera albicaulis Nutt. Head of Heart River, July 

 28th. 



61. CEnothera serrulata Nutt. Second Crossing of Heart 

 River, July 6th. 



62. CEnothera pinnatifida Nutt. Great Bend of Heart 

 River, June 23d. 



63. CEnothera csespitosa Nutt. Near Fort Rice, June 20th. 



LOASACEiE. 



64. Mentzelia nuda Linn. Shell Point, Yellowstone River, 

 July 16th. 



CACTACEiE. 



65. [Opuntia Missouriense D. C] Common at Fort Rice, 

 and increasing in abundance westward. In the Yellowstone Valley, 

 and between the Yellowstone and Musselshell Rivers, it often nearly 

 covers the ground for long distances. 



66. [Opuntia fragilis Nutt.] More or less common on the 

 prairies west of Fort Rice, but increases in abundance westward, in 

 places nearly covering the ground, and though smaller, is far more 

 troublesome to animals in traveling than the preceding species. 



67. [Mamillaria vivipara Nutt.] Common throughout the 

 region traversed. 



