69 



approach to cleistogamy doubtless harmonizes well with the 

 conditions of life under which these Arctic plants live. On the 

 other hand it is then of but slight biological importance that 

 the corollas are coloured and doubtless on the whole keep fresh 

 a very long time. (On this and on Cleistogamy in Campanula 

 uniflora see Warming, 1886, b, pp.150 — 154.) 



Of other peculiarities it is interesting to note the examples 

 of the ovary being protected by a similar covering of hairs as 

 are the vegetative parts, while the style is quite glabrous; here 

 again it is two of the open-flowering species, Ledum and 

 Bhododendron, which must be mentioned; of the others Phyl- 

 lodoce only (and Erica Tetralix]. 



Vaccinium- and Arctostaphi/los-specieé have fleshy fruits ; 

 the others have capsules. As examples of plants in which the 

 stalk of a drooping flower rises straight into the air when 

 the fruit becomes a capsule may be mentioned Cassiope and 

 Phyllodoce. In the nodding capsule in Ledum the position of 

 the valves is in harmony with this position of the fruit. 



In all the species the flowers are undoubtedly formed the 

 year previous to that in which they open; this has at any rate 

 been verified in the greater number of them. They are most 

 developed in Arctostaphylos alpina which is also the one to 

 flower the earliest in spring. Considering the shortness of the 

 summer it is evidently very useful that the development of 

 the flowers should be spread over two years. 



All the Greenland Ericaceae have woody stems and should 

 be referred to the growth-form called "dwarf-shrubs" (some 

 are of decided prostrate growth, e. g. Arctostaphylos alpina and 

 A. Uva-wsi)] Pirola however differs most in this respect. 

 The buds have typical scale-leaves in most of the species 

 (Arctostaphylos, Andromeda, Cassandra, Ledum, Vaccinium, etc.) ; 

 quite devoid of scale-leaves are Cassiope tetragona, the Arctic 

 heather which extends farthest towards the north, and Cassiope 



