70 P?-oceeih'nffs of the Uoi/al Irish Academy. 



without bloom, yellowish at first, grey in the second and third years, pubescent 

 with minute hairs ; pulvini slightly elevated; buds with little or no resin. 



Leaves with fragrant pine-apple odour, pectinate, either flat in one plane 

 or with a V-shaped depression between the two converging lateral sets, not 

 gflaucous, straight, 1 to 1^ inch long, thin ; apex acute or rounded ; lower surface 

 flat, with two well-defined whitish bauds of crowded minute stomata ; upper 

 surface with a distinct median groove from base to apex. A transverse 

 section of the leaf shows the proportion of breadth to thickness as 3'6 : 1 ; 

 epidermal cells of the under surface papillate ; hypoderm absent except in 

 the centre above and beneath ; idioblasts never present ; resin-canals with 

 two layers of lining cells. 



Female flowere conic, usually greenish, composed of small pointed erect 

 bracts, which are green with a narrow pink border ; seed-scales minute, with 

 ovules converging at the antipodal ends. In some trees the flowers are 

 reddish, so that colour alone will not distinguish this species from the 

 Colorado Douglas Fir. 



Cones when ripe 3 to 4 inches long, 1^ to 2 inches wide, light brown, 

 with numerous (about fifty) scales in ^^ phyllotaxis, and with erect 

 straight bracts. Scales thin, f-J inch wide, .slightly concave internally, 

 min>itely puWscent externally, rounded above witli a crcnulate margin. 

 Bracts erect, longer than the scales, with terminal slender awn and two 

 triangular, sharp-pointed, slightly laciniate lateral lobes. Seed about \ inch 

 long, dark shining reddish-brown above; light brown, mottled with white 

 l)eneath ; wing rounded at the summit, liafn gives the average weight of 

 1000 seeds as lOo grammes. 



The seedling has six to eight cotyledons about i; inch long, triangular in 

 section, entire in margin, green below and bluish above witli two stomatic 

 bands. Primary leaves alwut \ inch long, linear, sharp-pointed, grooved in the 

 median line above, with two stomatic bands beneath. Buds ovoid, reddish, 

 smooth, pointed. 



The Oregon Douglas Fir is a native of the Pacific coast region, which 

 includes southern British Columbia, Wasliington, and Oregon, from the crest of 

 the Cascade mountains to the sea, and the coast ranges of California as far 

 south as the Santa Lucia range. This species also occurs in the Sierra Nevada 

 range in California. 



The other principal trees of the Pacific coast region are Sitka Spruce, 

 Thuya gigantca, Western Hemlock, and Ahies fjraiuUs, with the Eedwood 

 limited to the coast of California. These are the largest trees in the world, 

 producing the maximum volume of timber per acre. The region is extremely 

 humid, with an annual rainfall of 60 to 100 inches, most of which falls in 



