42 



Knud Jessen. 



and longest stamens remain as a reserve which ensures self- 

 pollination (Fig. 16). 



Of a large collection of flowers preserved in spirit and 

 gathered at Upernivik on June 21, 1887, a great number 

 were found with more or less abortive stamens. All transi- 

 tions from normal to purely female flowers were found. The 

 abortive stamens were shorter than the head of pistils and 

 the anthers were small and shrunken, even in quite young 



flowers ; they con- 

 tained no pollen. The 

 carpels were appa- 

 rently normal though 

 the styles were some- 

 what short, but no 

 pollen was found on 

 the stigmas which 

 were furnished with 

 large papillæ, and 

 no fertilization had 

 taken place in the 

 older flowers. 



According to Er- 

 st am on Nova Zembla "Pot. fragiformis WiUd." is visited by 

 flies and other diptera. 



As is usual in the Potentillas the calyx is persistent and 

 closes around the fruits, whereby their dispersal is regulated. 

 The fruit-dispersal is anemophilous (Ekstam). 



Fig. 16. Potentilla emarginata. 



A, Longitudinal section through a flower; Vi. B, 



Pistil with hairs at the base ; stigma with many small 



conical protuberances; IK /i. Spitzbergen. (Drawn by Eug. 



Warming.) 



P. maculata E. M. vix Pour. 

 Syn. Potentilla alpestris Hall f. 



Lit. Hartz, 1894, p. 4; 1895 a., p. 288. Norman, 1895. 

 Abromeit, 1899. Andersson and Hesselman, 1900. Cleve, 

 1901. Sylvén, 1906. Wolf, 1908. 



The alcohol material is from Spitzbergen and Greenland 



