MEMOIRS FEOM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 107 



PotentUla divcrsifolia var. pinnatiseda Wats. King's Rep. 5 : 87. In part. 1871. 



Potentilla ooina J. M. Macoun, Can. Rec. Sci. 6: 464. 1895. 



Illustrations: Plate 46, f. 1 ; dissection of flower,/. 2; pistil,/. 3; stamen,/. 4; 

 fruiting hypanthium and calyx, / 5. 



Subcespitose. Stems mostly erect, less than 1 dm. high, strigose, with 2 or 3 re- 

 duced leaves, 3-6-flowered. Stipules smaller than in P. Plattensis, ovate, lanceolate, acute. 

 Basal leaves crowded, 2-4 cm. long, hoary, especially when, young, pinnate with many 

 crowded leaflets; leaflets deeply cleft into oblong obtuse lobes. Hypanthium hirsute, in 

 fruit about 8 mm. in diameter and erect; bractlets and sepals lanceolate, acute, the 

 former shorter. Corolla about 1 cm. in diameter. Petals obcordate, about a third longer 

 than the sepals. 



The specimens from which P. diversifolia pinnatisecta were described, viz. : Watson's 

 Nos. 331 and 332 of the King Expedition illustrate, I think, not less than three different 

 species. In the Gray Herbarium, No 331 is represented, as it seems, by a typical P. Plat- 

 tensis. This is doubtless the reason why Watson afterwards transferred the var. pinnati- 

 secta to that species. No. 332, which Watson, in King's Report, characterizes as an al- 

 pine more hairy form, is there represented by a specimen of what James Macoun 

 describes as P. ovina. This may be regarded as the typical P. pinnatisecta, as the other 

 forms of the collection are already named. In the Columbia Herbarium, No. 331 is rep- 

 resented by an unusually large form of P phinatisecta (P. ovina Macoun) and No. 332 

 by a depauperate specimen of P. Breioeri var. expansa Wats. 



The main differences between P. Plattensis and P. pinnatisecta are well pointed out by 

 Professor Nelson, /. c, only that his characterizing of P. Plattensis refers rather to the 

 most common, more prostrate form with narrow segments, mentioned below, and that 

 his specimens representing P. pinnatisecta are unusually large, less hairy and with longer 

 segments than usual. The typical form is subcespitose, seldom over 1 dm. high, with 

 nearly leafless flowering stems, smaller stipules than in P. Plattensis, and a densely hoary 

 pubescence, especially when young. It ranges from Colorado and Utah to British 

 America, and is a strictly alpine plant. Specimens examined : 



Colorado: C. S. Crandall, 1891; Osterhout, No. 7, 1897. 



Wyoming: F. H. Burglehaus, 1893; F. Tweedy; J. N. Rose, No. 385, 1893; C. C. 

 Parry, No. 97, 1873; Aven Nelson, No. 1819, 1895. 



Utah: S. Watson (King's Exp.) Nos. 331 and 332 (in part). 



Montana; W. M. Canby, No. 101, 1883; R. S. Wilhams, No. 753, 1888; Flodman, 

 Nos. 549, 550 and 551, 1896. 



British America: John Macoun, 1885. 



