Rosaceæ. 73^ 



flowers had no perfume, and he found homogamy only. Self- 

 polhnation is made possible by the fact that the anthers bend 

 over the stigmas or towards them. In 1898 the same author 

 writes regarding the flowers from Spitzbergen; here the dia- 

 meter was found to be 20, 25, 27 mm., exceptionally 28, 32, 

 and even 38 mm. (Müller records the diameter of the flower 

 in the Alps to be 27 — 40mm.; I.e.). Self-poflination may 

 easily take place as the anthers shed the pollen immediately 

 upon the stigmas. Honey is secreted between the androecium 

 and the gynoecium. Lastly, Dusén describes the flower-bio- 

 logy in East Greenland between 70° and 75°. He found 

 D. octopetala to be homogamous; regarding D. integrifolia he 

 writes that it is "dioecious (Ç)." 



In my material were 18 flowers (preserved in spirit) from 

 Bosekop in Arctic Norway (collected by Warming, 1885 ), of these 

 four were male, the others hermaphrodite; one of the latter 

 showed a distinctly proterandrous stage: almost all the sta- 

 mens had raised themselves into the air and had opened 

 their anthers, while the pistils were yet without papillæ. 

 The others were in a homogamous stage. Fig. 28, H shows 

 a rudimentary carpel from Bosekop; the ovule with the em- 

 bryo-sac is formed. Moreover, the material contained four 

 flowers gathered by Holm at Mejduscharskji(?) and probably 

 from Nova Zembla; three of these were distinctly male, the 

 rudimentary carpels did not rise above the hypanthium. In 

 the material was also found a male flower from Lille Sne- 

 næs in East Greenland. 



The insect-visitors in northern regions appear chiefly to 

 be flies and similar diptera (Lindman, Hartz and Ekstam). 



D. octopetala and D. integrifolia flower in early and middle 

 summer (June and August; Lange, Norman, Ekstam, 

 Andersson and Hesselman, and Simmons), and Ascherson 

 and Graebner (1. c.) record, as regards Central Europe, (May) 

 June and August. In Ellesmereland D. integrifolia is one of 



