82 MEMOIRS FEOM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 



Greenland: W. H. Burk, No. 24, 1891; Wm. E. Meehan, No. 22, 1892 (in part, 

 Upernavik), I. J. Hayes, No. 21, 1861.^ 



64. Potentilla Robbinsiana Oakes. 



Potentilla Robbin.v'cnia Oakes; Torr. & Gray, FJ. N. Am. 1 :441. As synonym. 1838. 



Rydberg, Bull. Torr. Bot. Club, 23 : 304 ; Britt. & Brown, 111. Fl. 2 : 211. 



Potentilla riiinhna fi Torr. & Gray, Fl. N. Am. 1 : 441. 1840. Beck, Bot. Ed. 2 : 99. 



Potentilla minima AValp. Eep. 2: 33, 1843; Gray, Man. Ed. 1 :122. 1848. 



Wood, Class Book, 342 ; Bot. & Fl. 107; Ann. 2 : 505, 1852. 



Potentilla fmj Ida Gray, Man. Ed. 2: 118, 1856; Ed. 5 : 154; Wats. & Coult. in 

 Gray, Man. Ed. 6 : 160, 1890 ; Wats. Proc. Am. Acad. 8 : 560. 



Potentilla minima Robbimiana Lehm. Eev. Pot. 159. 1856. 



Illustrations : Britt. & Brown, 111. Fl. 2 : /. 19:31. Plate 3:3, f. 6 ; dissection of 

 flower,/. 7 ; pistil,/. 8; stamen,/ 9; fruiting hypanthium and calyx,/ 10. 



Cestipose; stems 2-3 cm. high, softly long-pilose, one-flowered, and with 1 or 2 

 diminutive leaves. Stipules ovate, obtuse, scarious and brown. Leaves ternate, short- 

 petioled, villous-pilose especially beneath; leaflets obovate, cuneate at the base, deeply 

 incised serrate with generally obtuse teeth. Hypanthium villous, in fruit 5-7 mm. in 

 diameter ; bractlets and sepals oblong, obtuse, subequal. Petals obovate, slightly exceed- 

 ing the sepals. 



Torrey and Gray placed this species as a variety under P. minima and Gray trans- 

 ferred it to P. frigida. It very much resembles both of those European species It 

 comes nearest to P. minima in habit, but to P frigida in pubescence. It differs from 

 both m the small petals, which about equal the sepals, and in the bracts and the sepals 

 which are narrow and subequal. In both P frigida and P minMa the petals are longer 

 than the sepals and these much longer than the bractlets. The same characters that 

 distinguish P. Robbinsiana from the two species mentioned distinguish it also from its 



tZZTltr J""" ""'' '' ^- "'^'''^^^^ '' '''' '''^''''- I* ^PP--% is con- 

 bhis and O^^^^^ "'"" '' ""'" Hampshire, where it was first collected by Rob- 



Potentilla elegans Cham. & Schlecht. Linnaea. 2- 22 1827 



' Several other specimens are cited by Lange. 



