160 



has given a few notes regarding some individuals from East 

 Greenland, and writes: "very long year's-shoots; damp and 

 shady soil." In that place the greatest length-increment proved 

 to be 4 cm., with an average of about 2 cm. 



The yearly growth-increment of the short, erect shoot- 

 systems is naturally always much less than that of the prostrate 

 shoots, both in the regions of the far North and in cold 

 temperate zones ; and the difference of growth in the two 

 regions is much slighter than is that of the long shoots. In 

 Arctic regions the growth is less than one cm. Haglcnd (6,^ 

 p. 31), — who does not distinguish between the two kinds of 

 vegetative shoots, but states that the vegetative shoots are 

 "long shoots," — mentions that the growth of the year's- 

 shoots on the heath at Vassijaure averaged one cm. in 1903, 

 and that in the lowlands it was often 5 — 10 cm. This state- 

 ment is, however, worthless, as the two kinds of shoots are 

 not distinguished from each other. Kihlman (10, p. 226) reports 

 the length of the year's-shoots to be generally 1 — 2 cm., rarely 

 3 cm. 



When the connection between a branch-svstem and its 

 mother-axis is severed, a kind of vegetative propagation may 

 take place, but, as far as can be gathered from the literature 

 which deals with the subject this mode of reproduction does 

 not appear to be of great importance in the Arctic regions. 

 Hagldjnd alone mentions that on stony flats at Vassijaure it 

 plays an important part, as the fruit often does not ripen there. 



While the year's-shoot is quite young the epidermis is 

 covered with numerous glandular hairs, which afterwards, and 

 indeed fairly soon, fall off. Meanwhile, the outer walls of the 

 epidermis thicken to a varying extent, and on the fully grown 

 shoot, where these walls are very thick, more than one-half of 

 them is formed by a cuticularized layer which also extends 



The numerals refer throughout to the papers named in the list of 

 literature. 



