100 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



Montana: Electric Peak, Aug. i8, 1897, Rydberg & Bessey^ 

 4220; Indian Creek, July 22, 4221 ; Cedar Mountain, July 16, 4218 ; 

 Bridger Mountains, June 15, 422J and 4.226 ; Milk Creek, 1887, 

 Tweedy, ji; Helena, 1887, /^. W. Andersofi; Bozeman, 1892, 

 Mrs. Alderson ; Upper Marias Pass, 1883, Canby, 16, in part. 



Yellowstone Park : 1884, Tzveedv, 201. 



Idaho: Mt. Chauvet, July 29, 1897, Rydbei-g & Besscv, 42ig-. 



*Arabis microphyllaNutt. ; Torr. & Gray, Fl. N. Am. i : 82 [Syn. 



Fl. i>: 167]. 



Perennial, with several slender stems about 2 dm. high, from a 

 branching caudex ; leaves narrowly oblanceolate, stellate-pubescent 

 and with more or less ciliate petioles ; flowers small, rose-tinged ; 

 pods narro^v, erect or slightly spreading. On rocks, at an altitude 

 of 2000-3000 m. 



Arabis Drummondii Gray, Proc. Am. Acad. 6 : 187 [Syn. Fl. i' : 



166 ; Man. R. M. 20] ; Tiirritis stricta Grab. Ed. New Phil. 



Journ. 1829: 350. 



Rather common in the valleys, at an altitude of 2000-2500 m. 



Montana : Bridger Mountains, June 14, 1897, Rydberg d- Bcsscy, 

 42og; Park Co., 1887, Tzi'eedy, 2g; Bozeman, 1892, W. T. Shazv ; 

 Lewis & Clarke Co., Mrs. Miirfhy; Gallatin Co., Mrs. Alderson; 

 Granite, 1892,7^. D. Kelsey ; Bozeman, 1883, Seribner, 8g. 



Yellowstone Park: East De Lacy's Creek, Aug. 10, 1897, 

 Rydberg & Bessey, 4210; 1884, Tzueedy, igg; Mammoth Hot 

 Springs, 1885, Tzveedy, 557 ,* Stinking Water, 1873, Parry, 28. 



Arabis Lyallii Wats. Proc. Am. Acad. 9: 122 [Syn. Fl. i' : 166; 



Man. R. M. 20; Bot. Cal. i: 32]. 



Among rocks on the higher peaks, at an altitude of 2500-3500 m. 



Montana: Spanish Basin, 1895, Flodinan, joi ; Lake Plateau, 

 1897, P. Koch, jj ; Head of Stillwater, 6g; McDonald's Peak, 

 1883, Canby, 18 and ig: Upper Marias Pass, j6, in part. 



Yellowstone Park : 1884, Tzceedy, 202. 



Idaho: Mt. Chauvet, July 29, 1897, Rydberg d- Bessey, 4212. 



Erysimum cheiranthoides L. Sp. PI. 661 [111. Fl. 2: 151; Syn. 

 Fl. i' : 143; Man. R. M. 22]; Cheiranthiis cheiranthoides 

 Heller, Cat. N.Am. PL 4; Cheiranthiis titrritoides Lam. Enc. 

 2: 716. 



