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. Hacıuno (6,! 
p- 31), — who does not distinguish between the two kinds of 
vegetative shoots, but states that the vegetative shoots are 
“Jong 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. Kısıman (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-system 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. 
Hasrunp 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 
7 The numerals refer throughout to the papers named in the list of 
literature. 
