MEMOIRS OF THE NEU' YORK BOTANICAL GARDEN. S7 



LEMNACEAE. 



Lemna trisulca L. Sp. PI. 370 [Man. R. M. 360; 111. Fl. i : 366; 



Bot. Cal. 2: 189]. 



In shallow water up to an altitude of 2500 in. 



Montana : Great Falls, 1886, R. S. Williams^ fjp. 



Yellowstone Park: 1871, Robert Adams (Hayden Surv\) ; 

 1887, Knozflton; Yellowstone Lake, 1871, Hayden; 1872, Coulter. 



Lemna minor L. Sp. PI. 970 [Man. R. M. 360; 111. Fl. i: 366; 

 Bot. Cal. 2 : 190]. 



In stagnant water up to an altitude of 2000 m. 

 Montana: Helena, 1892, Kehcx. 



* Lemna cyclostasa (Ell.) Chev. Fl. Par. 2: 256; Lemna minor 



cyclostasa Ell. Bot. S. Ca. & Ga. 2: 518; L. Valdiviana Phil. 

 Linnaea, 33 : 239. 



Differs from L. minor in the lack of lateral veins on the fronds, 

 which are smaller, and in the orthotropous ovules. In stagnant water. 

 Yellowstone Park : Indian Creek, 1884, Tzceedy, j6. 



* Lemna gibba L. Sp. PI. 790 [111. Fl. i: 367; Bot. Cal. 2: 190]. 



Differs from X. minor by the fronds which are spongy gibbous 

 beneath. It grows in ponds and slow streams up to an altitude of 

 2500 m. 



Yellowstone Park: Broad Creek, 1S85, Tzceedy, ^10. 



COMMELINACEAE. 



* Tradescantia occidentalis Britton : Tradescantia Virginiana occi- 



dentalis Britton, 111. Fl. i : 377. 



It differs from the eastern T. Virginiea in the longer and nar- 

 rower leaves and the smaller flowers. It grows in sandy soil in the 

 prairie and plain regions, reaching an altitude of 1200 m. 



Montana: Big Horn River, 189 1, Tzveedy. 



JUNCACEAE. 



Juncus Balticus Willd. Berhn Mag. 3: 298 [Man. R. M. 357; 



111. Fl. i: 384; Bot. Cal. 2: 205]. 



In meadows, especially in alkaline soil, up to an altitude of 

 2500 m. 



Montana: Lima, 1895, 7?)'rt''^^r^S 2072 and 2^08: Deer Lodge, 

 21J1 ; Melrose, Shear, 343; Forks of Madison, July 26, 1897, Ryd- 



