MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 1 27 



Polygonum emersum (Michx.) Britton, Trans. N. Y. Acad. Sci. 8: 

 73 [111- Fl. i: 556: Small, Mon. 44]; Polygonum amphibiwn 

 cmcrswn Michx. Fl. Bor. Am. i : 240; Polxgomini Muhlenbcrgii 

 S. Wats. Proc. Am. Acad. 14: 295 [Man. R. M. 320; Bot. 

 Cal. 2: 13]. 



In wet places up to an altitude of 1800 m. 

 Montana: Logan, 1895, Rydbcrg; 261 j; Gallatin Co., Mrs. 



Alderson; Bozeman, 1886, Tzccedy, 1201 ; Great Falls, 1886, R. 



S. Williams, ^80; Box Elder Creek, 1887, <^^i/ Missouri River, 



1883, Scribiier, 2j8 : Missoula, 1880, Watson. 



Polygonum Hartwrightii Gray, Proc. Am. Acad. 8: 294 [Man. R. 



M. 320; 111. Fl. i: 556; Bot. Cal. 2 : 14 ; Small, Mon. 42]. 



Borders of lakes and ponds up to an altitude of 1600 m. ; rare. 



Montana : Bozeman, 1886, P. Koch, 1202, in part ; Bozeman, 

 1886, Tzveedy, 1201; Missoula, 1898, Williams & Griffith. 



Polygonum lapathifolium nodosum (Pers.) Small, Mem. Torr. Bot 

 Club, 5: 140 [111. Fl. i: 557 -.Small, Mon. 55]; Polygonum 

 nodosum Pers. Syn. i: 440 [Man. R. M. 320; Bot. Cal. 2: 13]. 

 In wet places up to an altitude of 2000 m. 

 Montana: Bozeman, 1886, P. Koch, 1200; W. T. Shaw; Little 



Prickly Pear Creek, 1883, Scribncr, 2jp. 



Polygonum lapathifolium incanum (Smith) Koch, Syn. Fl. Germ. 

 711 [Man. R. M. 319; 111. Fl. i : 557 ; Small, Mon. 54] : Poly- 

 gvntifn incannm Smith, Fl. Boem. 4: 90. 

 In low lands up to an altitude of 1500 m. 

 Montana : East Gallatin Swamps, 1896, Flodman, jSy. 



* Polygonum Persicaria L. Sp. PI. 361 [111. Fl. i: 558; Small, 



Mon. 66']. 



Differs from P. la^athifoliwn by the bristle-fringed ocreae and the 

 dark blotch on the leaves. It belongs to the prairie region, but ex- 

 tends along the Yellowstone up to an altitude of about 1500 m. 



Montana: Big Timber, i^c)-!, Kelsey. 



* Polygonum littorale Link ; Schrad. Journ. i : 54 [111. Fl. i : 562 ; 



Small, Mon. 102]. 



Differs from P. avicitlare in the more obtuse leaves and the style, 

 which is 3-parted to the base. In sandy soil up to an altitude of 

 2500 m. 



Montana: Cottonwood Creek, 1896, Flodman, jgS; Helena, 



