40 



names as: Pinus ponderosa var. scopulorum, Pinus ponderosa var. 

 Jeffrey!, Pinus contorta var. Murrayana, Pseudotsuga Douglasii var. 

 glauca, are liable to give rise to inaccuracies. It is not long since 

 seed of Contorta and Murrayana were not distinguished in the 

 market; it was the same with the Green and Blue Douglas Fir. 

 This was, and indeed is, a very simple system for the merchants 

 who deal with seeds like shopkeepers with raisins. It is therefore 

 a great advantage for tree growers to deal with as few varieties 

 and forms as possible. In all cases, where practicable, the limits 

 of the species should be as narrow as possible. 



THE DOUGLAS FIR PSEUDOTSUGA DOUGLASII 

 AND PSEUDOTSUGA GLAUCA 



The difficulty of avoiding clumsy triple names again meets us 

 here. In the first instance I think the difference between the green 

 Coast Douglas and the glaucous or grey Rocky Mountain Douglas 

 is so great, that I am justified in following H. Mayr* in regarding 

 the two as distinct species. 



It is indeed possible that the future may show that the boundary 

 between the two species cannot be made a strict one. Seed im- 

 ported by the Deutsche Dendrologische Gesellschaft from Ques- 

 nel, at the source of the Frazer River in British Columbia, pro- 

 duces plants which point in this direction. Apparently they ap- 

 proach the grey form very closely in colour, and the Coast Douglas 

 in rapidity of growth. The future will show if we are here dealing 

 simply with a hybrid between the green and grey species. Un- 

 fortunately I have never been able to obtain either seeds or cones 

 of this Quesnel Douglas (Ps. Doug, caesia) for testing; perhaps the 

 seed weight would have shown us something of interest. As may 

 be seen from the Table, the large number of Douglas samples I 

 have submitted for testing during the years have taught us nothing 

 of the influence of the place of origin on the seed weight. 32 Samples 

 of the green species have an average seed weight of 10.3, and 15 

 samples of the grey species 11.3 grams. The difference is so small, 

 that it may be owing to the fact that the seed from the Rocky 

 Mountains is generally better cleaned than that from the coast of 

 the Pacific. In the year 1912, for the first time, I received for testing, 



* Heinrich Mayr: Fremdlandische Wald-und Parkbaume fur Europa. 



