310 PINUS ALBICAULIS. 



Pinus albicaulis. 



A tree of variable height, usually 20 30, rarely 60 feet high, 

 with a trunk 2- 4 feet in diameter ; at high altitudes reduced to a 

 low shrub with spreading stems. Bark thin, broken by narrow fissures 

 into light brown or creamy white scales. Branchlets stoutish, reddish 

 brown. Buds broadly ovate, acute, with chestnut-brown perulse loosely 

 imbricated. Leaves quinate (in fives), persistent five eight years, stout, 

 rigid, slightly incurved, 1*5 3 inches long, dark green. Stamina te 

 flowers in short spikes, oval, with scarlet anthers and surrounded at 

 the base by eight nine involucral bracts. Cones sessile, ovoid or 

 sub-globose, 1/5 3 inches, with much thickened, gradually pointed scales, 

 the exposed portion contracted on both sides to a sharp edge, and 

 bearing a stout, nearly triangular, incurved tip. Seeds nearly 

 0'5 inch long, with very narrow, thin wings. Sargent, Silra of 

 North America, XL 39, t. 548. 



Pinus albicaulis, Engelmann in Trans. Acad. Sc. St. Louis. II. 209 (1863). 

 Lawson, Pinet. Brit. I. 1, with tigs. Hooker iil in Gard. Chron. XXIV. (1885), 

 p. 9, with fig. Beissner, Nadelholzk. 274. Macoun, Cat. Ca-nad. Plants, 465. 

 Masters in Journ. R. Hort. Soc. XIV. 225. 



P. flexilis var. albicaulis, Engelmann in Brewer and Watson's Bot. Califor. II. 124. 



An alpine tree spread over the high mountains of north-west 

 America at altitudes ranging from 5,000 to 12,000 feet, growing on 

 the most exposed ridges where it forms the timber line on many 

 of them. It is abundant on the mountains of southern British 

 Columbia, whence it spreads southwards into the United States along 

 the Eocky Mountains to Wyoming, and along the Cascade mountains 

 of Washington and Oregon into California, reaching its southern 

 limit on the San Bernardino mountains. 



Pinus albicaulis affords a remarkable instance of endurance and 

 tenacity of life under exceptionally severe conditions, and in places 

 where probably no other vegetation could exist. On bleak and lofty 

 ridges, and in wind-swept passes battling with perpetual snows, its 

 trunk is stunted, and its branches gnarled ; it is also exposed in 

 places to fierce winds thickly charged with sand, which denude the 

 trunk of its bark and erode and furrow its hard wood. Under these 

 adverse influences the trees sometimes become flat-topped, and so close- 

 roofed with condensed branchlets and foliage that one may walk safely 

 on them. The short, thick stems of some of these trees are probably 

 over five hundred years old.* 



The species was discovered in 1851 on the mountains of ^Xorth 

 Oregon by Jeffrey the collector of the Scottish Oregon Association and 

 introduced by him ; but the unsuitableness of the British climate for 

 it has long since been proved, and very few plants of it are to be 

 seen in this country. Its place is better filled by its nearest affinity 

 Pinus flexilis from which it differs chiefly in its paler bark and smaller 

 globose cones, the scales of which are much more thickened and 

 terminate in a short incurved tip. 



* Lemmon, North-west American Cone Bearers, 25. 



