14 MINNESOTA BOTANICAL STUDIES. 



III. SOME EXTENSIONS OF PLANT RANGES. 



Edmund P. Sheldon. 



Potamogeton heterophyllus Schreb 



forma myriophyllus (Robbins). Morong. Naiad. N. Am. 24. 

 1898. 



Not previously reported from Minnesota. 



Abundant in lake Mora, Kanabec county, Minn. {E. P. S., 

 July, 1892. ) Found also in Page lake, Carver county, Minn. 

 (C. A. Ballard, August, 1892). A form which seems to be 

 intermediate between the above and forma minima Morong, 

 was found in a pond near Milaca, Mille Lacs county, Minn. {E. 

 P. S., July, 1892). It has the dichotomously branched stems 

 of the former and the small, one nerved, submerged leaves and 

 clustered floating leaves of the latter. 



Jiiiieiis greenii Oakes & Tuckerm. Am. Jour. Sci. I, 

 14:: 37. 1843. 



Not previously reported from Minnesota. Sandy soil near 

 Zumbrota, Goodhue county, Minn. (C. A. Ballard, August, 1892). 

 I am indebted to Mr. F. V. Coville for the determination of this 

 plant. 



Polygonum rigid ulum n. sp. (Plate I). 



Perennial, aquatic, stout, somewhat rigid, 8 — 6 feet high, 

 branching above the base, immersed portions of the stem much 

 swollen, geniculate, rooting at the nodes, tapering upward from 

 each node, glabrous below, minutely scabrous above with short 

 appressed hairs; leaves 3 — 7 inches in length, erect, not floating, 

 obliquely attached to the petioles, the lower ovate or roundly 

 obcuneate, with petioles as long as the blade, mostly glabrous 

 or with short, appressed hairs on the veins underneath, the 

 upper oblong-lanceolate, acuminate, glabrous or finely pubes- 

 cent; spikes elongated, in pairs; flowers pale rose color; fruit 

 orbicular, smooth and shining. 



