Rosaceæ. 41 



According to Lange the flowering period in Green- 

 land is in July — August, and on Nova Zembla the plant 

 flowers in the middle of summer and late in autumn (Ек- 

 stam)^; but Hartz found it in flower on Præstefjæld in 

 Greenland on June 15, and at Scoresby Sound on June 19; 

 in Ellesmereland the flowering begins in the middle of June 

 and is continued into August (Simmons). In my alcohol 

 material there were numerous flowers from Upernivik gathered 

 on June 21. Pot. frag if orm is WiM. f. parviflora Trautw., which 

 is perhaps a synonym of Pot. emarginata (cf. Wolf, p. 533), 

 according to Andersson and Hesselman (1. с), is a spring 

 plant in Spitzbergen; it flowers in the middle of June and 

 in the beginning of July. Pot. emarginata sets fruit abun- 

 dantly (Ekstam, Simmons). 



The large, pale yeflow flowers occur either singly or 

 2 — 3 together on the floral shoot. Wolf states the diameter to 

 be 15 — 18 ( — 20) mm., Ekstam records 20 mm. from Nova 

 Zembla, while Pot. fragiformis f. parvißora from Spitzbergen has 

 flowers only 10 — 14 mm. broad (A. and H.). Ekstam found 

 no scent, but he found honey which is secreted between the 

 stamens and on the base of the filaments. He was of opinion that 

 homogamy and self-pollination were possible as the stamens 

 were bending over the stigmas. Of the stamens the 5 inner- 

 most are the longest and in the spirit-material they were 

 only very shghtly separated from the stigmas. Warming 

 writes in his notes regarding specimens from Spitzbergen that 

 these 5 antesepalous stamens which he also found to be the 

 longest, are without doubt easily able to shed pollen upon 

 the stigmas. They open later than do the others. I also 

 find that Pot. emarginata is homogamous (Upernivik and Lille 

 Snenæs), perhaps with a short proterogynous stage. In case 

 polfination fails for some reason or other, the 5 innermost 



' See note, p. 36. 



