MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 93 



generally sessile. It is generally quite hairy with long and yellowish white hairs. In 

 general habit and flowers it conies near P. Vahliana, which has been mistaken for it; but 

 the latter has always only 3 leaflets. 



Spitzbergen, Greenland, arctic coast of America, and Wrangel Island, eastern 

 Siberia. 



Qirmhmd: H. C. Hart; Parry; Dr. Hayes, No. 20, 1861 ; A. Hartz, No. 8022, 1890.^ 

 Arctic Amo-Uxi: R. Bell, No. 1454, 1884 (Hudson Strait); No. 1480a (Diggs Island); 



1893 (Cape Prince of Wales); J. W. Tyrrell, 1893 (lat. 64°, long. 100°).; Dr. Bissel 



(Polaris Bay). 



Wrangel Island: J. Muir, 1881. 



74. Potentilla litoralis Rydberg. 



PotentiUa litoralh Rydberg, Bull. Torr. Bot. Club, 23 : 264. 1896. 



Britton & Brown, 111. Fl. 2 : 214. 



Pofe7^;^7/aPe7^w.s///;vm/•mGray, Man. 122, 1848; Gray Man. Ed. 2 : 119; Ed. 5 : 154;=^ 

 Wood, Class Book, 343 f Bot. & Flor. 108 f Wats. Proc. Am. Acad. 8 : 553 f Wats. & 

 Coult. in Gray, Man. Ed. 6 : 159.^ 



Illustrations : Britt. & Brown, 111. Fl. 2 : /. 1930. Plate S7, f. 1 ; dissection of 

 flower, /. 2 ; stamen, /. 3 ; pistil, /. 4 ; fruiting hypanthium and calyx, /. 5. 



Stem decumbent or ascending, 2-4 dm. long, simple, slightly appressed silky-strigose. 

 Lower stipules lanceolate, scarious aiad brown, the upper ovate, green, more or less 

 toothed. Leaves pinnate, of two approximate pairs of leaflets, the lower pair the smaller, 

 or subdigitately 5-foliolate, grayish tomentose and veiny beneath, nearly glabrous above, 

 Leaflets obovate, divided to near the midrib into linear oblong obtuse divisions. Hypan- 

 thium strigose and slightly tomentose, in fruit about 8 mm. in diameter. Bractlets lan- 

 ceolate-oblong, nearly equalling the ovate-triangular sepals. Petals obovate, cuneate, 

 truncate or slightly emarginate, about equalling the calyx. Stamens 20-25. Style short, 

 terminal, thickened and glandular at the base. Achenes smooth. 



A near relative of P Pcn'iisyhxvnica, but differs in the ascending or spreading stem, 

 the sparser pubescence, the leaves, which have fewer and approximate leaflets, often almost 

 digitate, and the sepals which are more distinctly ribbed. P. litoralis is principally a beach 

 plant, or at least growing near the coast, while P Pennsylvanica is an inland, plain or 

 mountain species. The following specimens belong to P. litoralis. 



'Several other specimens are cited by Lange aud Rosenvinge. ^ Includes also the true P. Pennsylranka. 



