12 



The Pines 



a conic head, but in old age it is more rounded in outline. The bark of old trees 

 is 2.5 to 5 cm. thick, deeply fissured into broad ridges and square, dark brown 

 to nearly black scaly plates; on younger stems it is simply scaly and lighter in 

 color. The twigs are very tough and flexible, light orange-colored, softly hairy, 

 soon becoming smooth and darker, sometimes purple and covered by loose, dr}'ish 



brown scales; the termi- 

 nal buds are about 12 

 mm. long, twice the length 

 of the lateral ones. The 

 l eave s are in fascicles of 

 5, without permanent 

 sheaths, stout and stiff, 

 about 5 cm., rarely 9 cm. 

 long, and entire, or in a 

 southern form, slightly 

 toothed near the apex, 

 marked on the upper 

 faces with i to 4 rows of 

 stomata and contain 2 

 Rocky Mountain White Pine. resin-ducts and a single 



fibrovascular bundle; they form tufts at the ends of the twigs and persist for about 

 six years. The flower s appear late in June, the staminate in clusters at the end of 

 the twigs; they are oval, about 12 mm. long, their anthers reddish. The pistillate 

 flowers are in nearly terminal clusters of 2 or 3, nearly sessile, about 12 mm. long, 

 bright reddish purple and subtended by persistent, dryish brown bracts. The 

 cones, growing rapidly the second summer, have fully matured by SeptembePj^wften 

 they are horizontal or slightly declined, stout-stalked,<^va"l or nearly cylindric, 7.5 to 

 25 cm. long, about 4 cm. thick, fight brown, shedding the seeds and usually falling 

 off before winter; their scales are thin, usually broad and rounded with a thickened 

 darker knob, scarcely reflexed at the apex, the basal ones sterile, narrower and 

 much reflexed, the unexposed portion dull reddish brown. Seeds oval, compressed, 

 8 to 12 mm. long, dark reddish brown and mottled, the margin narrow, the wing 

 thin, dull, about 12 mm, wide, remaining attached to the cone-scale, the seed fall- 

 ing away from it; cotyledons 6 to 9. 



The wood is soft, close-grained, pale yellow or reddish on exposure; its specific 

 gravity is about 0.43 ; it is used in the southern part of its range for construction, 

 but is not as good as that of Pinus Strohus, being ver>' knotty. 



l-IG. 6. 



6. WHITE BARK PINE Pinus albicaulis Engelmann 



A rather small tree of alpine habitat, occurring at altitudes of 1500 to 3600 

 meters, in the high mountains of British Columbia southward to the San Bernardino 

 Mountains of southern Cafifomia, eastward to Montana and Wyoming. Its 



