476 ABIETIA DOUGLASII. 



of the somewhat vaguely defined difference observable in its growth 

 and aspect.* Looked at from every point of view Fortune's Fir comes 

 nearest to the Douglas Fir, and is here provisionally joined with it. 

 These Firs are intermediate forms ; the Douglas Fir bridges over the 

 difference between the Hemlock and Silver Firs, and Fortune's Fir the 

 difference between the Spruce and Silver Firs ; moreover the Spruce 

 Firs are connected with the Hemlocks by the flat-leaved species of 

 the section Omorica. Whilst for practical purposes it may be the most 

 convenient course to retain the different groups of Firs under separate 

 generic names, doubts may reasonably arise whether that course is 

 most compatible with a strictly scientific classification of them, seeing 

 that all the Firs have, like all the Pines, easily recognisable common 

 characters, and like the Pines are connected together by discernible links. 



Abietia Douglasii. 



A tree of very variable dimensions, under favourable conditions in 

 Washington and Oregon near the Pacific coast, 175 200 or more 

 feet with a trunk 4 6*5 feet in diameter, and where the trees are 

 crowded, usually denuded of branches for one-half or more of the 



Fig. 121. Branchlet of Abietia 



!! with foliage and staminate flowers. 



height and with a thin narrow crown, which in very old trees 

 Incomes flat-topped ; t on the drier slopes of the Rocky Mountains not 

 more than 80 100 feet high with a trunk 2 3 feet in diameter ; 

 even reduced to a low shrub at its highest vertical limit. Bark 

 of adult trees 3 5 inches thick, reddish brown, deeply and irregularly 

 fissured ; in the forests of Oregon and Vancouver Island often much thicker 

 and separated into broad rounded ridges broken on the surface into dark 

 red-brown scales. In Great Britain the oldest trees have a pyramidal 

 outline much broken by projecting branches. Bark of trunk dark brown 

 and much fissured, the general direction of the fissures longitudinal and 



* Sa vegetation, ainsi que son facies general, out egalement quelque chose de particulier 

 qni lie se rencontre dans aucun genre ni meme dans aucune section etablis, p. 262. 

 . t Individual trees have been felled in the neighbourhood of Puget Sound over 250 feet 

 high with trunks 5 to 7 feet in diameter. A section of an exceptionally large tree preserved 

 in the Natural History Museum at South Kensington is about 7 feet in diameter. 



