MEMOIRS FEOM THE DEPARTMENT OF BOTANY OP COLUMBIA UNIVERSITY 89 



Potcnfilla nirca uitijlunt- Rydberg, Bull. Torr. Bot. Club, 23: 303. 1896. 



Potentll/a nimi VahlUviin Wats. Bibl. Index, 1 : 298. In part. 



Illustrations: Lelim. Mon. yl. 18. Plate 35, f. 3 ; dissection of flower, /. 4; 

 pistil, f. 5; stamen, /'. 6; fruiting hypanthium and calyx, /. 7. 



Densely cespitose, the caudox covered with the dark brown scarious stipules and re- 

 mains of old lea^'es. Stems about 5 cm. high, more slender than in 7^. VahhUiwt, slightly 

 villous or tomentose, nearly scapose or with few very small leaves, 1-2-flowered. Leaves 

 crowded, ternate, silky or glabrate above, densely white-tomentose beneath ; leaflets 

 1-1.5 cQi. long, broadly cuneate or rhombic-obovate, deeply cut from the apex into 

 coarse oblong lanceolate teeth. Flowers 15-20 mm. in diameter. Hypanthium white 

 or gra3'ish, villous or somewhat tomentose, about 8 mm. in diameter; bractlets oblong or 

 lanceolate, nearly equalling the ovate lanceolate acute sepals. Petals yellow, obcordate, 

 nearly twice as long as the sepals. 



The true position of this plant is difficult to determine. It may be placed as a va- 

 riety of P nivca or of P. Vahlvvna or as a species intermediate between the two. Lede- 

 bour made it a varietj^ of P. villosa, which it somewhat resembles as to the leaves. It 

 has the cespitose habit, short nearly leafless stems, and short wedge-shaped leaves of P. 

 Vahliana. Its flowers are nearly of the same size as those of that species, but the petals 

 are obcordate, not obreniform, and the sepals and bracts are those of P. nivea, depauperate 

 forms of which may grade into it. It is found in the arctic regions from Greenland to 

 Alaska and adjacent Asia, but also in the Rocky Mountains to Colorado. Apparentl}^ 

 all specimens labelled P. nivea VuhJia-na from the Rockies belong to P. uniflora. It was 

 evidently this form that Watson had in mind when he made the statement that P. 

 Vahliana was a depauperate few-flowered form of P. nivca. 



Colorado: H. N. Patterson, 1885; No. 195, 1892; C. S. Crandall; C. F. Baker, No. 

 18, 1896; Alice Eastwood, 1892; G. G. Parry; T. S. Brandegee, 1880; G. E. Osterhout, 

 1893. 



Montana: W. M. Ganby, No. 104. 



Oregon: Dr. Lyall, 1861. 



Alberta: J. Macoun, No. 7. 1897. 



British Columbia: John Macoun, No. 33, 1890. 



Rocky Mountains: E. Bourgeau, 1853 ; J. Macoun, No. 639, 1885; No. 1481, 1879; 

 No. 7332, 1890; Nos. 7331 and 7338, 1891. 



Greenland: H. E. Wetherill, No. 18, 1894. 



