2o6 transactions—PERTHSHIRE SOCIETY OF NATURAL SCIENCE. 
Viola silvestris, Reich. 
Cerastium triviale, Link. 
Hypericum pulchrum, L. 
Oxalis Acetosella, L. 
Vicia Cracca, L. 
Lathyrus montanus, Bernh. 
Fragaria vesca, L. 
Potentilla Fragariastrum, Ehrh. 
P. silvestris, Neck. 
Circsea lutetiana, L. 
Galium saxatile, L. 
Valeriana officinalis, L. 
Scabiosa succisa, L. 
Scrophularia nodosa, L. 
Melampyrum pratense, L. 
Veronica officinalis, L. 
V. Chamaedrys, L. 
Teucrium Scorodonia, L. 
Ajuga reptans, L, 
Pteris aquilina, L. 
Anthyrium Filix-foemina, Roth. 
Lastrsea Filix-mas, Presl. 
Dicranum scoparium, Hedw. 
Atrichum undulatum, L. 
Polytrichum commune, L. 
Hypnum cupressiforme. Dill. 
H. purum, L. 
The distribution of the oak includes the greater part of Europe, 
and even Western Asia in the region of the Caucasus. The oak 
association shows much greater variety of species in its continental 
range than that of beech, although throughout it preserves the general 
characteristics of the vegetation. 
The Scots Pine, Pinus sylvestris^ L.—The pine is grown on 
almost every soil in our valley, and at all altitudes below 2000 feet 
(Hooker places its upper limit in Britain at 2200 feet). The chief 
condition for its growth is light, and one sees how its lower branches 
gradually die off under the shade of the dense crown above. It seeds 
freely and, if unaffected in its distribution by man, seems to prefer 
the following habitats :— 
1. Sandy plains, e.g.^ Tentsmuir. 
2. Summits of crags and similar dry, rocky places, e.g.^ 
Craigiebarns. 
3. Damp, peaty soil, e.g,, Cairnleith Moss, near Bankfoot. 
I have also remarked it in similar situations in Norway, in the 
Hardanger region. Warming mentions it for similar situations in 
Denmark, etc., while M. Christ, in Switzerland, notes its occurrence 
on the first and second. 
As we shall see further on, there is a great similarity between the 
habitats just mentioned and those in which we find Callima, In 
fact, certain investigators believe that Calluna is originally a sub¬ 
ordinate plant of the pine forest, and that it is owing to the changes 
brought about by man in deforestation and sheep-pasturing that the 
area of Calluna has been increased (Krause). There is little doubt 
that much of the present heath land was formerly covered by forest, 
and even now we can see the natural regeneration continually going 
