MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 267 



Euphorbia serpyllifolia Pers. Syn. 2 : 14 [111. Fl. 2 : 372 ; Man. R. 



M. 326]. 



In sandy soil, up to an altitude of 1500 m. 



Montana: Sun River, 1883, Scribner, 2^g; Missoula, 1898, 

 Williams & Griffith. 



Yellowstone Park: Upper Geyser Basin, 1885, Tzueedy, 44J. 



Euphorbia glyptosperma Engelm. Bot. Mex. Bound. Surv. 187 [III. 



Fl. 2: 373; Man. R. M. 326]. 



In sandy soil, up to an altitude of about 2500 m. 



Montana: Custer Co., 1892, J/r^. Light: Helena, \^^2, Kchey, 



Yellowstone Park: Lower Geyser Basin, Aug. 4, 1897, Kyd- 

 berg & Bcssey, jg^j ; Upper Basin, Aug. 6, 3^44. 



Euphorbia raarginata Pursh, Fl. Am. Sept. 607 [111. Fl. 2: 376; 



Man. R. M. 327]. 



On prairies and in pastures, up to an altitude of 1000 m. 



Montana: Custer Co., 1897, Mrs. Light; N. E. Montana, 1892, 

 Br. Hollflivay; Miles City, 1886, Peter Koch, 11 00. 



Euphorbia dictyosperma F. & M. Ind. Sem. Hort. Petrop. 2: 37 



[111. Fl. 2: 379; Man. R. M. 327]. 



On prairies, up to an altitude of 2000 m. 



Montana: Helena, 1888 and 1890, F. D. Kclsey ; Hell Gate 

 Canon, 1880, Watson. 



Euphorbia robusta (Engelm.) Small, in Britton & Brown, 111. FL 



2 : 381 ; EiipJiorbia moiitaiia -i robitsta Engelm. Bot. Mex. Bound. 



Surv. 192; Euphorbia moiitana Coulter, Man. R. M. 327, in 



part. 



Dry hills, up to an aldtude of 2000 m. 



Montana: Livingston, 1889, Tweedy; Shields River, 1883, 

 Scribner, 2jo; Sand Coulee, 1892, R. S. Williams, j^y ; Missoula, 

 1882, Tiveedy, jyd. 



CALLITRICHACEAE. 



Callitriche palustris L. Sp. PI. 969 [111. Fl. 2: 382] ; Callitriche 



verna L. Fl. Suec. Ed. 2 : 4 [Man. R. M. 328]. 



In ponds and slow streams, up to an altitude of 2500 m. 



Montana : Jack Creek, July 16, 1897, Rydberg & Bessey, 43 ig; 

 Sand Coulee, 1891, R. S. Williams, 621. 



Yellowstone Park: Lower Falls, 1871, T. C. Porter. 



