International Excursion in America. 91 
over again. The causes of the occupation of so much of the 
country by Douglas forest would then be the long duration of the 
Douglas stage and the frequency of fires. This view is not, however, 
shared by all authorities well acquainted with the country. 
Pseudotsuga comes in very early on land once burned over. 
Arbutus Meuziesii, whose headquarters are in the sugar-pine 
(Pinus Lumbertiaua) area on the Californian Sierra, extends up the 
the coast through Oregon as far as Vancouver Island, where it 
occurs mainly on warm dry slopes. A few trees occur so far inland 
as this Rainier area. The distribution of this species furnishes an 
interesting parallel with that of Arbutus Unedo in Europe, whose 
headquarters are in a warm dry region, but which extends up the 
west coast so far north as south-west Ireland. In both cases the 
mild winters of these northern coast-regions are no doubt the 
factor which makes such a distribution possible. 
The shrubby undergrowth consists of Acer circulation, A. 
glabrum, Ribes bracteosum, Rubus spectabilis, Vacciniumparvifolium, 
Berberis nervosa, Gaultheria Shallon, etc. These and the ground- 
flora form, however, a very open vegetation on account of the 
dense shade. In clearings or on areas recently burned over 
Epilobium angustifolium and Pteridium aquilinum are very con¬ 
spicuous, exactly as they are in similar situations in north-west 
Europe. In the deep shade of the forest itself the herbaceous 
vegetation is rather sparse and consists of such species as the 
tall Devil’s Club ( Echinopanax horrida) which is abundant and 
conspicuous, Cornus canadensis (a northern herbaceous species much 
like the European Cornus suecica), Maianthemum bifolium var. 
dilatation, Smilacina sp., Tiarella, etc., with abundant ferns— 
Blechnum boreale, Polystichum munition, Phegopteris Dryopteris, 
Athyrium cyclosorum. These together with many of the angio- 
spermous herbs frequently grow on the immense fallen logs met 
with in every direction and covered with thick carpets and cushions 
of mosses and liverworts. 
Dicotyledonous trees are practically absent from the Douglas 
forests, but often form a belt along the stream-sides. Alnus oregana, 
Acer macrophyllum and A. circulation are the chief species in such 
situations, with Populus trichocarpa (closely allied to P. balsamifera), 
and Fraxinus oregana. 
The Douglas woods extend up to about 2,000 or 2,500 feet, and 
as one ascends are gradually replaced by mixed woods of Abies 
amabilis, A. nobilis, Tsuga heteropliylla, Pinus mouticola, Chanue - 
cyparis nootkatensis (the Alaska cedar). The ground-vegetation 
