NOTES ON THE DOUGLAS FIR. 25 



Plateau or the Interior Wet Belt. The majority of the cones 

 I collected in the Coast forests were damaged by a tortrix 

 {Rhyacionia sp?), which apparently devours the seed. 1 was 

 able to obtain only small supplies of good cones. 



Three different varieties of the Douglas fir are thus evidently 

 to be found in British Columbia, which can be recognised by 

 the structure of the cones and the botanical characteristics of 

 the seedlings. These three varieties, which are distinguished 

 by Canadian foresters as the Dry Belt Douglas fir, the Mountain 

 Douglas fir, and the Coast Douglas fir, have the following 

 distribution : — 



1. The Dry Belt Douglas fir (? the Glauca form). Confined 

 to the Interior Plateau, and possibly found only in the southern 

 portion of that region. The more important associate species 

 are Pinus ponderosa, Picea Engelmafini, Pinus Alurrayana. 



2. The Mountain Douglas fir, Caesia variety, occurs in two 

 regions with somewhat different climatic conditions : — 



(i) In the Interior Wet Belt, comprising the Cariboo and 

 Monashee Mountains and the western slopes of the Selkirk 

 Mountains. 



(2) In the Rocky Mountains and the eastern slopes of the 

 Selkirk Mountains. 



The more important associate species in these regions are, 

 Thuya gigantea, Picea Engehnanni, Tsuga heterophylia, Pinus 

 monticola, Pinus Murrayafia, and Abies lasiocarpa. 



3. The Coast Douglas fir occurs in regions west of the 

 Cascade and Coast Mountains. The more important associate 

 species are Thuya gigantea, Tsuga heterophylla, Picea sitchensis, 

 Abies grandis, Abies amabilis, Pinus Murrayatia. 



The western larch {Larix occidentalis) has not been noted as 

 occurring in any of the above regions. This species occupies 

 a peculiar position, being found in localities that cannot be 

 regarded as belonging either to the Dry Belt or the Interior 

 Wet Belt, but in a zone that marks the borderland between 

 the two. 



There are also probably in existence varieties of the Douglas 

 fir itself that are correctly to be regarded as intermediate forms 

 between the more typical forms. 



In The Forests of British Columbia the authors say : — 



" As one traverses the low passes of the southern Coast 

 Mountains, it will be noted that as the Dry Belt 



