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IOWA ACADEMY OF SCIENCE 
ture of true Canadian forms, though these do not comprise a 
very large part of the total number. Such are Pinus monticola, 
Clintonia uniflora, Tiarella unifoUata, Chimaphila umhellata, 
Pentstemon, fruticosa, and Senscio triangularis. The dense for- 
ests that cover most of this region are made up of Pseudotsuga 
mucronata (comprising at least half of the total bulk), Thuja 
plicata, Abies grandis, Tsuga heterophylla, Pinus monticola, and 
an occasional Pinus lambertmna. There are numerous unforested 
slopes and ridges, mostly supporting a dense growth of shrubs 
of various species. Along the banks of the river is an abundant 
growth of Taxus hrevifolia, Alnus oregana, and Acer circinatum. 
From McKenzie Bridge a three days’ trip was made to Horse 
Pasture Mountain, ten miles to the southwest. This mountain 
has an elevation of about 2000 meters. The sides are mainly 
forested but the summit is mostly bare of trees and carries the 
flora quite through the Canadian zone, which is represented by 
a long list of species. Near the summit occurs Tsuga mertensi- 
ana and several other typically Hudsonian forms. 
From McKenzie Bridge to the summit of the Cascades by way 
of the McKenzie Pass is about twenty miles. The road follows 
the canyon of Lost creek, a tributary of the McKenzie. Most 
of the way of ascent is gradual. Nearly half of the distance 
is through the usual dense forest, but the eastern half is through 
a more open region, mostly covered with undergrowth and in- 
tersected by sharp, ridges and peaks with numerous slides of 
black porous lava. The elevation at the summit is approxi- 
mately 1600 meters. 
The flora at this point is high Canadian, about equivalent to 
that found at the top of Horse Pasture Mountain, where the 
elevation was somewhat greater. The divide does not form a 
sharply defined ridge, but there is a considerable area of mod- 
erately level country, with occasional shallow ponds, furnishing 
suitable conditions for a great variety of plant life. For the 
most part, the forest is not dense. The dominant tree is Pinus 
contorta, with a considerable abundance of Pinus monticola, 
Tsuga mertensiana, Abies nobilis, and in places, Pseudotsuga 
mucronata and Picea engelmanni. Deciduous trees are wanting 
and shrubs are small and not abundant. The latter are : one or 
two species of Salix, Bibes lacustre, Spiraea densifiora, Pyrus 
sitcJiensis, Gaultheria ovadifolia, Vaccinium scoparium, and V. 
macropJiyllum. Among herbaceous plants, species of Carex, Ra- 
