42 



CRUCIFER2E. 



6. Erysimum Arkansanum Nutt. Crossing of the Big 



Muddy, July 1st. A common prairie species from the Missouri to the 

 Yellowstone. 



7. Erysimum asperum var. ineonspicuum S. Watson. 

 Crossing of the Big Muddy, July 1st. 



8. Vesicaria Ludoviciana D. C. Prairies, west of Fort 

 Rice, June 22d. 



9. Physaria didymocarpa Gray. Valley of the Little Mis- 

 souri, at the mouth of Davis Creek, July 10th. 



10. Lepidium Virginicum L. Valley of the Little Mis- 

 souri, July 10th. 



CAPPARIDACE^. 



11. Polanisia uniglandulosa D. C. Shell Point, Yellow- 

 stone River, July 16th. Abundant in sandy places. 



12. Cleome integrifolia Nutt. Valley of the Musselshell, 

 August 20th. Common. 



CARYOPHYLLACE^ 



13. Cerastium arvense Linn. Valley of the Musselshell. 



14. Paronychia sessiliflora Nutt. Near the Big Muddy, 

 July 3d. 



MALVACEiE. 



15. Malvastrum coccineum Gray. Sparingly on the prai- 

 ries from Fort Rice to the Yellowstone, June 18th, and later. Also 

 found in blossom in the bottom lands of the Yellowstone, August 

 8th, where the growth of this and other plants had been retarded by 

 the spring overflow of the river. 



LINACE^. 



16. Linum sulcatum Riddell. Crossing of the Big Muddy, 

 July 1st. Seen also on Heart River, but not common. 



17. Linum perenne L. Abundant on the dry plains and 

 prairies everywhere, varying greatly in size and appearance at differ- 

 ent localities. 



ANACARDIACE2E. 



18. Rhus toxicodendron Linn. Along the Missouri at Fort 

 Rice, and also on Heart River. 



