THE FLORA 413 
occurrence which I found in such situations are: Oxytropis 
campestris (rare), Arctostaphylos alpina, Loiseleuria pro- 
cumbens (rare), Vaccinium uliginosum, V. Vitis-[dea, var. 
minus, Diapensia Lapponica (growing in little rounded 
mounds on its own previous growth, very branchy, showing 
yearly additions outward and upward, — one specimen I 
examined was three inches in diameter and one and a half 
inches highin the centre); willows, Empetrum nigrum, Carex 
rigida (rare), Festuca brevifolia (rare); three mosses (Di- 
cranum, Polytricum  strictum, Racomitrium lanuginosum), 
and a lichen (Umbilicaria). Dead roots and branches, 
especially of the willows and Hricacee, were frequent, and 
on them grew other varieties of moss. Labrador tea and 
grasses flourished on the edges of these bare patches, where 
some soil had already been formed. 
(c) ‘Shallow depressions of the tundra, where the water 
of melted snow and ice accumulates in the soil, become 
swamps in the form of tundra-moor, and there a scanty peat 
bears a thin layer of sphagnum with a few small phanero- 
gams. Such places correspond physically but not physi- 
ologically to the oases of the dry desert’’ (Schimper). 
The moor presents many features that are unfavourable to 
the life of plants. Humous acids are abundant and pre- 
vent the easy absorption of moisture; mineral substances 
are hard to obtain, ‘‘ owing to the great distance of the vege- 
tation from the mineral substratum and to the absorptive 
influence of humus, rendering it difficult for the plants to 
obtain soluble salts”; nitrogen is abundant, but in such 
form that the moor is among the poorest of soils in easily 
assimilable nitrogenous substances. Sphagnum is the 
characteristic and most abundant plant in such situations. 
