410 



Andii. Ll'nüa(.kh 



had ht'cn pciu'lraliiii; the snoNV-coverin«^, therefore the under [)arl of 

 the snow-crust and the upper layer of the soil, especially that which 

 stood highest (to the north), was frozen ice. Here also a Melandrinm 

 was found. The soil around the Ceraslium and at its root was (juite 

 dry, as dry as dust. The plant had fresh shoots besides green 

 leaves that had remained through the winter. (F'or the biology of 

 the llower see Warming, 189Ü, Festskrift, p. 197, figs. 1, 2). 



Ranunculus glacialis L. Homogamy the rule. The nectar-pit is 

 without a scale. (For the biology of the flower see Knud Jessen 

 in Meddel, o. Grönland XXXVI, p. 338, fig. 3). 



Within the Cruciferœ there is a considerable contrast between 



Lesquerella arctica, which 

 is decidedly xerophilous 

 (as also Bray a in part) 

 and the majority of the 

 Drabas, most of which 

 may be found both in dry 

 and in damp soil. Draba 

 glacialis associates itself 

 with any other plant (as 

 also does Cardamine belli- 

 difolia) both in the driest 

 gravel and in the wettest 

 moss; and no change can 

 be observed in its appear- 

 ance as it occurs in the 

 one or the other place. 



The Pollination of Cam- 

 panula uniflora. When in 

 the young bud the anthers 

 and the stigma are at the same level, the anthers begin to open, 

 but the lobes of the stigma keep close together and their apices are 

 bent inward toward each other Fig. 18 A, B). At this time no polli- 

 nation can take place by the help of outward agencies, the corolla 

 being closed. And as long as the anthers are at a higher level than 

 the stigma, the former are quite closed and then the pistil with its 

 sweeping hairs is also without pollen. But the style elongates 

 rapidly in the yet closed flower and with its hairs sweeps off all the 

 pollen from the open anthers (Fig. 18 C) so that its upper thicker 

 part is everywhere coloured by the pollen. All the pollen is now 

 to be found there, with the exception of a small portion which is 

 left on the inner surface of the anthers. The flower opens simul- 

 taneously with the elongation of the style; but not until the pistil 



Fig. 18. Campanula uniflora. 



