58 MONTANA AGRICULTURAL COLLEGE SCIENCE STUDIES. 



N^ar A. Holboclii, Hornem., with which it is commonly confused, 

 but differs from this in being lower and more slender, stems glabrous 

 above, less sagittate cauline leaves, pods about half as long and wide 

 and more appressed and seeds in one row. From A. arcnata snbi'illosa, 

 Wats, it is separated by its lower, more slender habit and its smaller, 

 appressed, straight pods. In appearance it closely resembles A. 

 c.i'ilis, Nelson (Bull. Torr. Bot. Club, 26:123), but differs in its sagit- 

 tate cauline leaves, narrower pods and winged seeds. 



Frequent in dry rocky glades in the mountains from 5-7000 ft... 

 while the larger wide-fruited A. Holboclii belongs to the plains and 

 lower valleys. Named for Peter Koch of Bozeman, Mont., who so 

 long collected industriously the flora of this region and gave his 

 work to advance the cause of science. 



Plains, Missoula Co., June 6, 1902; Lower Canyon of the Gallatin 

 River, 5500 ft., July 5, 1898; Lower Basin of the Gallatin, 6000 ft., 

 July 6, -1898; Bridger Canyon, 5000 ft., July 20, 1898; Lombard, June 

 I, 1901. 



Barbarea stricta, Amirz. Flowers smaller and a paler yellow, 

 fruiting raceme strict, separating it from B. vulgaris arcuata, Fries, 

 which also occurs here, but less frequently. 



Spring Hill, July 3, 1903, Amy M. Cooke; Evaro, June 8, 1902; 

 Yellowstone, E. N. Brandegee. 



*Brassica campestris, L. A frequent weed in old fields and 

 waste places. Bozeman, July 22, 1898; Craig, July 29, 1900; Sales- 

 ville, Sept. 2, 1892, W. T. Shaw. 



*Brassica juncea, Cosson. A rare introduction. Bozeman, 

 July 27, 1903, Amy M. Cooke. 



*Brassica nigra, Koch. Not infrequent as a weed in fields and 

 waste places. Great Falls, 1900; Alhambra, July 24, 1898, E. X. 

 Brandegee; St. Ignatius, Sept. 7, 1899; Wibaux, July 9, 1901; Crow 

 Agency, July 15, 1901; N. Boulder, June 25, 1899, C. D. Flaherty. 



Cardamine acuminata, Rydberg, Bull. Torr. Bot. Club, 29:237; 

 C. hirsiita aciuninata, Nutt. Middle Cr., June 3, 1900; Gallatin River, 

 June 28, 1899; Columbia Falls, June 2, 1894, R. S. Williams, 338; 

 Belt R. Canyon, June 21, 1885, R. S. Williams; Bozeman, July 23, 

 1898. 



*Conryngia perfoliata, Link. Introduced in a few localities, 

 Hinsdale, June 13, 1901 ; Midvale, July 19, 1903, L. M. Umbach. , 



