266 MEMOIRS OF THE NE^V YORK BOTANICAL GARDEN. 



4517^ Park Co., 1889, Tzuecdy ; Warm Springs, 1892, Kelscy ; 

 Great Falls, 1891, R. S. Williams, 144; Gallatin Co., Mrs. Alder- 

 son; T>Q.Q.x\^o6.gQ. 0,0., Misses Hobsou'iVCidi Ware; 1892, W. T. Shazu.. 

 Yellowstone Park : iQS'i,, Miss Mary Compton; 1885, Tzvecdy, 

 792- 



Linum rigidum Pursh, Fl. Am. Sept. 210 [Man. R. M. 42; Svn. 



Fl. i^: 347; 111. Fl. 2: 351]. 



On dry plains and hills, scarcely reaching an altitude of 2000 m. 



Montana: Manhattan, 1895, Rydberg, 2724; Fort Custer, 1891, 

 Tweedy ; Great Falls, 1891, 7?. S. Williams, i^j : Lewis and Clarke 

 Co., Mrs. Miith; Custer Co., 1892, Mrs. Light. 



POLYGALACEAE. 



Polygala alba Nutt. Gen. 2 : 87 [Man. R. M. 30 : Syn. Fl. i' : 455 ;. 



111. Fl. 2: 360]. 



On prairies and plains, up to an altitude of 2000 m. 



Montana: Big Timber, 1887, Tweedy, 227; Custer Co., 1892, 

 Mrs. Light. 



EUPHORBIACEAE. 

 * Euphorbia albicaulis. 



Depressed, divaricately many-branched ; stems and branches slen- 

 der, very light greenish 3'ellovv, glabrous and shining ; leaves very 

 short-petioled, light green, linear, i-nerved, entire or minutely cal- 

 lous-toothed towards the apex, 1-1.5 cm. long and 2-3 mm. wide; 

 involucre very small, about i mm. in diameter, turbinate ; append- 

 ages minute, rather broad, truncate and crenulate, white ; pod acutely 

 angled, smooth, 2 mm. long; seeds light brown, oblong, acutely 4- 

 angled, 1.3— 1.5 mm. long, less than 0.5 mm. broad, slightly cross- 

 wrinkled. 



Nearest related to E. scrpyllifolia, from which it differs in the 

 much narrower leaves, broader appendages, and the seeds which are 

 brown, and always lack the white bloom usual in E. serpyllifolia. 

 The narrow leaves, the slender branches and light color of the plant 

 x^mxn^'i on^ oi E . pet alo idea, \)\!i\. the appendages are minute and the 

 seeds much smaller, narrower and sharpl}' 4-angled. It grows in 

 sandy soil and in cultivated ground, at an altitude of about 1500 m. 



Nebraska: Cheyenne Co., 1891, Rydherg, jj6 (type). 



Montana: Beaver Head Co., 1888, Tzveedy, 124. 



