74 Proceedings of the Roijol Irish Academy. 



About fifty of these trees iu the Queen's Cottage Giouuds, Kew Gardens, 

 are healthy, but comparatively slow iu growth. They were 7 to 10 feet higli 

 in 1919, forming narrow regular pyramidal trees, with ascending branches. 

 Tliey differ from the type in not making a summer shoot. At Avoudale, a 

 small plot, nine years old from seed, average 5 to 8 feet high, about half 

 the height of Oregon Douglas Fir of the same age planted beside them. In 

 Germany also, var. cacsia grows more slowly than the Oregon Douglas Fir, 

 and can be recommended for planting only in northern and mountain 

 climates, where it would probably withstand severe winter frosts. 



Fseadotsaga glauca. Colorado Douglas Fir. 



Psrudotmga ylaucxi, Mayr, in Mill. Beidsch. Dendr. Ges. 1902, p. 86. 

 Paeudotsuga Dowjlasii, \&i\ glanca, Mayr, ll'ald. N&rdamer. 307 (1890). 



The Colorado Douglas Fir attains about 80 or 90 feet in lieigiit. Young 

 brauchlets either glaucous and reddisli brown in the first three seasons, 

 or without bloom, when they become grey in the second or tliird year ; 

 pubescence variable, oft«n glabrous on terminal branches, and pubescent on 

 lateral branchlets ; pulvini elevated, projecting at the apex. Buds resinous, 

 more or less covered with a whitish deposit of resin. 



Leaves with strong odour of turpentine, not regularly pectinate, those in 

 the middle line spreading irregulaily, and more or less upturned on the 

 branchlets ; similar to P. Voiiylasii in length and breadth, but tiiicker, and 

 convex beneath ; upjjer surface indistinctly grooved, the median furrow not 

 continued to the apex ; lower surface with two bands of crowded large 

 stomata. A transverse section shows the ratio of breadth to thickness as 

 2*4 : 1 ; epidermal cells all papillate ; hyiioderm nearly continuous all round ; 

 idioblasts numerous ; resin-canals with two layers of lining cells. 



Female flowers irregular in shape, with widely spreading reflexed bracts, 

 brilliant pink in colour, more rounded than in the Oregon species. Seed- 

 scales with ovules diverging at the antipodal ends. 



Cones, when ripe, 2 to 3 inches long, l\ inch broad, light brown, with 

 comparatively few (about 30) scales in -^^ phyllotaxis, and with reflexed 

 spreading bracts. Scales somewhat smaller than in P. Douglasii, more 

 concave internally, pubescent externally ; rounded above with entire margin. 

 Bracts reflexed about the middle, and spreading outwards ; median awn 

 slender, with triangular acute lateral lobes. Seeds similar to P. Douglasii, 

 with paler wings, liafn gives the average weight of 1000 seeds as ITS 

 grammes. 



PieudoUuga glaiico is a native of the central and southern Kocky Moun- 

 tains, extending from eastern Montana and Wyoming southwards through 



