1074 The Trees of Great Britain and Ireland 



into the dense mixed coniferous forest of the surrounding mountains. Plate 281, 

 from a negative taken by Prof. Elrod, represents a yellow pine near Flathead Lake. 

 Near Whitefish, Henry measured an average tree, 148 ft. in height and 1 1 ft. in girth, 

 which showed when felled 3J in. thick of bark, 3 in. of sapwood, and 360 annual rings. 

 In the Blackfoot valley, near Missoula, I measured a tree 140 ft. high by 15 ft. in girth. 



In Colorado the mountain form ' forms very extensive pure forests on the 

 plateau between 7000 and 8200 ft., ascending occasionally to 9000 ft., and descending 

 to 4500 ft. Here the tree rarely exceeds 80 ft. in height and 3 ft. in diameter. It 

 extends southwards along both sides of the Rockies to western Texas, northern 

 New Mexico, and Arizona, exhibiting in the latter state several peculiar forms, 

 which have been distinguished, on account of their very long needles and peculiar 

 cones, as distinct species (P. Mayriana, P. apachecd). It also spreads into the 

 northern states of Mexico 2 in varieties with leaves varying in number, distinguished 

 as P. macrophylla and P. arizonica, the latter being also a native of Arizona. 



In wet regions, like the coast of British Columbia and Vancouver Island, the 

 tree is unknown ; but it grows in Washington, close to Puget Sound, on dry gravelly 

 prairies. In eastern Washington it forms an open pure forest on the lower timber 

 line, bordering on the arid region, and ranges from 400 to 6200 ft. According to 

 Piper, 8 it has a marked preference for granitic soil, though it grows on basaltic clay in 

 the Blue Mountains. It here attains its maximum development at 2000 ft., reaching a 

 height of 200 ft. and a diameter of 6 ft. It is common along the eastern slopes and 

 foothills of the Cascade range, and becomes a conspicuous tree in southern Oregon, 

 where the climate is drier, forming considerable forests at Grant's Pass and in the 

 Siskiyou mountains. 



In California it occurs in the coast ranges, 4 as in Sonoma and Napa counties, 

 and there is a fine forest of this species on the Howell mountain plateau ; but no trees 

 are known in the inner coast ranges bounding Solano and Yolo counties. It is not 

 recorded from the San Francisco Bay ranges, except from the Mt. Hamilton ridges. 

 It is abundant in the Sierra Nevada, at or above 5000 ft. ; and, according to Muir, 5 

 ranges on the western slope from 2000 ft. to timber line, and, crossing the range by the 

 lowest passes, descends to the eastern base, and pushes far out into the hot volcanic 

 plains. The largest tree measured by Muir grew in the Merced valley, and was 

 220 ft. high and 8 ft. in diameter. 



Var. Jeffreyi occurs in California, 6 from Scott's Mountain in Siskiyou county, 

 and along the eastern slopes of the Sierra Nevada, forming large forests at the 

 headwaters of the Pitt and M 'Cloud rivers, and often grows on the most exposed and 

 driest ridges, wandering out among the volcanoes of the Great Basin. Sudworth 

 records it from Douglas county in southern Oregon ; and it is the chief pine on the 

 lower slopes of Mount Shasta, which it ascends to about 5500 ft., the largest that I 



1 A tree growing in Monument Park, Colorado, is figured by Sir J. Hooker in Gard. Chroti. ix. 796, fig. 138 (1878). 

 ! Shaw, op. cit. 2, states that P. ponderosa extends in Mexico southwards to lat. 23 or 24. 



3 Contrib. U.S. Nat. Herb. xi. 50, 92, tt. xiv. xv. (1906). 



4 Jepson, Flora W. Mid. California, 21 (1901). 6 In Harper's Magazine, xxii. 7 1 9. 



6 Sir J. Hooker, in Gard. Chron. xxii. 814, fig. 141 (1884), gives a sketch of a tree growing in the Silver Mountains in 

 the Sierra Nevada range, on the eastern slope, and says he met with no specimens nearly so large as 200 ft., the height given 

 by Sargent. 



