32 



Knud Jessen. 



of the intensely yellow petals which are either of one col o ur- 

 or have an orange-coloured spot at the base. Honey is secre- 

 ted abundantly." According to Wolf the diameter of the 

 flower is 10 — 15 to 18 mm. The flowers in my material from 

 northern Norway and from Greenland were homogamous,, 

 and appeared to behave like those of P. emarginata. The 



five innermost stamens which stand 

 before the sepals are longer than 

 the others and rise upwards almost 

 to the level of the pistils. In flow- 

 ers from Kongsvold and Alten in 

 Norway it could be seen how the 

 somewhat outwardly bent styles 

 touched with their stigmas the 

 open anthers of these stamens. 

 Warming (1. c.) also finds that 

 the anthers and stigmas are deve- 

 loped simultaneously "and the sta- 

 mens stand so erect and close to 

 the pistils that self-pollination must undoubtedly easily take 

 place (Fig. 11, ,4)." In Scoresby Sound Hartz (1. c. 1895 a) 

 observed Syrphids to visit the flowers of P. nivea. 



Norman records that the flowering period is in the latter 

 half of July and in the first half of August; Cleve: from 

 June 30th to July 10th; Lange: July — August in Greenland 

 where Hartz, however, in 1889, 1890 and 1892 found it flowering 

 in the middle of June. In tke botanical museum of Copen- 

 hagen there are flowering specimens from different places in 

 N. Greenland gathered at the end of June. 



P. nivea sets fruit abundantly probably everywhere. 

 Fruit-dispersal is as in P. emarginata. Greenland specimens 

 gathered on the 4th of February on ground free from snow 

 had ripe fruit enclosed between the contracted sepals, and 

 Warming (notes) found (July 15) fruit from the preceding 

 year hidden in the same manner. 



Fig. 11. Potentilla niven. 



A. Longitudinal section through a 

 flower from Spitzbergen (about 2 /i). 

 Drawn by Eug. Warming. B, 

 Carpel showing the peg-shaped cells 

 at the base of the style (about -' 1). 



