Rosaceæ. 21 



The leaf-stalk is also stiffened, in addition to the fibrous 

 tissue of the bundles, by some collenchyma which at the 

 angles attains a thickness of several layers. The outer wall 

 of the epidermis is also strong. 



The open, cymose inflorescence is few- to many-flowered. 

 The entire petals are white, and the stamens — 20 in num- 

 ber — have very long reddish filaments. The diameter of the 

 flower is 10 — 15 mm. (Wolf). The flower is scentless; there 

 is a greenish yellow disk around the base of the stamens; 

 the intensely flesh-coloured anthers appear to dehisce before 

 the stigma is functional (Warming's notes). Investigation 

 of about 10 flowers preserved in spirit and collected from 

 different districts in Greenland showed that the minute 

 stigma of the long styles does not bear papillæ even in flowers 

 which were so old that the anthers had fallen from the fila- 

 ments. In spite of a close search I found only one pollen- 

 grain upon a stigma; among the crowded long hairs of the 

 gynophore much pollen is usually found in older flowers. 

 The anthers form pollen abundantly, which is, apparently, 

 capable of germination. Warming states in his notes that 

 in some inflorescences from the previous year from different 

 localities in Greenland he found a few fruits which appeared 

 to be ripe. Hartz (1894) found Pot. tridentata in flower on 

 Præstefjæld on June 15, 1890; the flowering is continued 

 into September. 



Potentilla pulchella R. Br. 



Lit. Andersson and Hesselman, 1900. Simmons, 1906. 

 Wolf, 1908. Lundager, 1912. 



This is a purely Arctic species; it grows in Spitzbergen, 

 Greenland, Arctic North America and on Wrangel Island off 

 N. E, Siberia. Its habitats are rocky and grassy flats. — The 

 alcohol material I had for investigation was from Snenæs in 

 N. E. Greenland and Tempel Bay in Spitzbergen. 



