MONTANA AGRICULTURAL COLLEGE SCIENCE STUDIES. 



The true S. nivalis, L. is a species of the Arctic regions and is 

 readily separated from* this species of the Rocky Mountains by its 

 glabrate, canescent or sparse purple-glandular pubescence ; its wider, 

 more rounded, thinner serrate-dentate leaf-blades; wider calyx-tube 

 and shorter petals. The nearest relative of S. Grccnci in the Rockies 

 is S. rhomboidea, Greene (Pittonia, 3:343), which is a much larger 

 plant with interruptedly spicate inflorescence, longer (4 mm.) 

 petals , more viscid pubescence and found in lower situations (3-8000 

 feet). 



'Mt. Hyalite, Aug. i, 1902, 10,000 ft.; Black Butte, Tobacco Root 

 Range, Aug. 1 1, 1902, 10,000 ft. ; Dewey, June 24, 1902, 9000 ft. ; Flat- 

 top Mountain, Teton Co., July 5, 1897, 7000 ft., R. S. Williams; 

 Red Lodge, June, 1899, J. M. Kay; Old Hollowtop, near Pony, July 

 9, 1897, Rydberg & Bessey, 4267; Lake Plateau, Aug. I, 1897, Peter 

 Koch. 



In alpine and subalpine situations throughout the Rocky Moun- 

 tain region, passing in lower situations into S. rhomboidea and proba- 

 bly in the extreme north into 6". nivalis. [PLATE I, A and B]. 



Sa.vifraga nivalis, Rydberg, Flora, 194, and other authors as to 

 the Kocl.v Mountain specimens. All specimens so nn tried ?rom this 

 region must be divided between S. rhomboidea, Greene, and the 

 smaller S. Greenei above. The true S. nivalis is confined to the Arc- 

 tic regions. 



Saxifraga Marshall!!, Greene, Pittonia, i: 159. 5\ occidentalis, 

 Wats., Proc. Amer. Acad. 23 1264, in part ; .S. sa.nmontana, E. Nel- 

 son, Erythea, 7:168; S. Idahocnsis, Piper, Bull. Torr. Bot. Club, 27: 

 394. A careful study of this group convinces me that these are all 

 one species. Small (Bull. Torr. Bot. Club, 23:362) would limit 

 6\ occidentalis, Wats, to the specimens cited from Vancouver Island, 

 which have larger petals (4 mm. long), sepals nearly always erect 

 even in fruit, glabrous stems and leaves rufous-tomentous beneath 

 and marked by Watson "n. sp.," although in publication he first 

 cited the Rocky Mountain specimens of Drummond, which are 

 identical with those here considered and previously described by 

 Greene as S. Marshallii. Nelson and Piper appear to have in mind 

 only the form with purple-glandular pubescent stem, nearly glabrous 

 leaves and small flowers. Our species appears to vary considerably 

 in the size of the petals (1.^2-3 mm.) and hight of the plants (1-3 

 dm.), but none appear to have the "oval green spot on each side 

 of the midnerve toward the base" of the petals, mentioned by 



