359 
The Ecology of the Driva Valley. 
specimens of Platysma Fahlnnense occupied a considerable space, 
and quite a notable feature of this area was that peculiar but 
characteristic lichen Thamnolia vermicularis, occurring in a scattered 
manner over other lichens and mosses, sometimes in patches, but 
more often as solitary plants. 
Among the exposed rocks were fairly dry patches of turf, and 
in some of the hollows small peaty pools were the breeding places 
of numerous mosquitos. 
The drier parts of this turf were tenanted principally by 
Einpetmm nigrum and Betula nana, while amongst these two plants 
were scattered individuals of Vaccinium uliginosuw, V. Vitis-idxea, 
Arctostaphylos Uva-ursi, A. alpina, Azalea procumbens, Phaca frigida, 
Hieraceum alpinum, Antennaria dioica, young plants of Salix 
lanata, S. phylicifolia, S. glauca, various hybrid willows, Luzula 
spicata, and Carex rigida. Rather feebly grown plants of Juniperus 
nana also occurred, the older branches being covered with fine 
fruiting specimens of Platysma juniperinum. Near the edges of this 
turf, close to the rocks, were small patches of Alsine hirta, A stricta , 
and A. biflora. 
In and about the wet hollows, in which there were frequently 
small pools, were Eriophorum polystachyon, E. vaginatum, Carex 
ampullacea, C. ustulata, C. capillaris, Polygonum viviparum 
Rubus Chamcemorus, and fine masses of Saxifraga aizoides. Small 
scattered patches of Sphagnum fuscum, S. rubellum, Amblyodon 
dealbatus , Cinclidium stygium, Hypnuni falcatum, H, uncinatum 
v. abbreviation, and a peculiar form of H. filiciuum also occurred. 
Extensive vertical faces of rock, especially near the river, were 
often covered with the brilliantly coloured lichen Placodium elegans, 
the deep reddish-orange colouration having a characteristic effect 
on the nearer landscape. 
The rocks of the roadside were sometimes almost covered with 
Salix reticulata and Saxifraga oppositifolia; and rock-debris, if 
in the shade, was largely covered by Cystopteris montana. Either 
Silene acaulis or Dryas octopetala was occasionally dominant, and 
plants of Potentilla Crantzii were sometimes very numerous. 
The composition of this rock flora varied considerably as one 
travelled down the road, even where the conditions were uniform. 
A good sample, near the Sprenboekken, was as follows :—Poa 
alpina (20), Galium boreale (16), Campanula rot undifolia (16) 
Potentilla Crantzii (16), Achillea Millefolium (15), Astragalus 
alpinus (9), individuals of a considerable variety of plants (8). The 
