MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 91 



whole plant is covered with yellowish villous hairs besides the tomentum. Lehmann 

 was in some doubt whether he should regard it as a variety of P. nivca, or as a distinct 

 species. He made it a species on the authority of Vahl, who knew the plant in its native 

 habitat. Seeing only P. nivca and P. Vahliana nobody would hesitate in assigning 

 specific rank to the latter. The trouble arises Avhen one is to draw the line between 

 either and P. uniflora. Lehmann states that P. Vahliana was collected by Richardson in 

 Captain Franklin's journey. Specimens collected by Richardson and named P. Vahliana 

 are in the Torrey Herbarium at Columbia, but these belong to P. uniflora. There is, 

 however, from the same collector one specimen, a very small one, indeed, which without 

 any doubt belongs to P. Vahliana, but this is, together with two specimens of P. nana, 

 under the name P. nivea arctica. Except this specimen and one from Herald Island, all 

 specimens seen are from Greenland and the islands of Hudson and Baffin Bay. They 

 are generally labelled P. pulchella. The latter species is easily distinguished by its small 

 flowers, the petals scarcely exceeding the sepals, and its deeply dissected leaves which 

 are pinnate with two approximate pairs of leaflets. 



Greenland: Dr. H. E. Wetherill, Nos. 70 and 82, 1894; No. 174, 1894; Vahl; Rink; 

 L. Krumlein, 1877-8; William E. Meehan, No. 19, 1892; W. H. Burk, No. 21, 1891.' 



Herschell Island: Rev. J. D. Stringer, 1893. 



Arctic Coast of North America : Richardson. 



Hudson Bay: J. W. Tyrrell, No. 7254, 1893 (Marble Island). 



Herald Island: Capt. C. L. Hooper, 1881. 



§ 15. MULTIFIDAE, 



72. Potentilla Sommerfeltii Lehm. 



Potentilla Somraerfeltii Lehm. Del. Sem. Hort. Bot. Hamb. 1849 : 6. 1849. 



Lehm. Stirp. Pug. 9:4; Rev. Pot. 37 ; Walp. Ann. 2 : 474 ; Lange, Consp. Fl. 

 Groen. 4 ; Rydberg, Bull. Torr. Bot. Club, 23 : 265. 



Illustrations : Lehm. Rev. Pot. pi. 10, f. 2. Plate 35, f. 1 ; ^pistil, /. 2. 



Cespitose ; caudex covered with the brown scarious broadly ovate stipules. Stem 3- 

 5 cm. high, slightly silky, scapose, 1-2-flowered. Leaves pinnate, of two pairs of leaflets, 

 and a stalked terminal one, glabrate above, finely tomentose beneath ; leaflets obovate 

 in outline, divided to near the middle into linear-oblong obtuse segments. Bractlets 

 oblong, obtuse, much shorter than the similar sepals. Petals obovate-cuneate, a little 

 exceeding the sepals. 



' Sevoral other specimens are cited by Lange and Rosenvinge. 



