108 SILVA OF NORTH AMERICA. conifers. 



generally in a single layer. 1 The staminate flowers are produced in elongated spikes, and are 

 cylindrical and about half an inch long, with orange-brown anthers terminating in irregularly toothed 

 broad crests, and are surrounded by six involucral bracts. The pistillate flowers are borne in fascicles 

 of from two to four flowers, several fascicles often appearing on the shoot of the year, and are raised 

 on short peduncles covered by broadly ovate dark chestnut-brown bracts scarious and fimbriate on the 

 margins; they are oblong and about one half of an inch in length, with ovate scales terminating 

 in long slender recurved points. At the end of the first season the young cones are erect, slightly 

 spreading or nearly horizontal, broadly ovate, and about an inch long, with ovate incurved scales 

 narrowed into slender rigid tips; and a year later, when fully grown, they are elongated-conical, 

 pointed, very oblique at the base by a greater development of the scales on the upper side than on 

 the lower side, short-stalked, strongly reflexed and incurved, from three to six inches long, from an 

 inch and three quarters to two inches and a half thick, and light chestnut-brown, with thin flat scales 

 rounded at the apex, those on the outside being enlarged into prominent transversely flattened knobs 

 armed with thick flattened incurved spines, and turn upward above the middle of the cone, and are 

 nearly straight below, while on the inner side of the cone the exposed portions of the scales are only 

 slightly thickened and transversely keeled, and terminate in small dark umbos armed with minute 

 recurved prickles. The cones remain on the stems and branches for thirty or forty years, often 

 becoming completely imbedded in the bark of old trees, and usually not opening until the death of 

 the tree, when they all open at once and scatter their seeds, although occasionally some of the oldest 

 cones open during the life of the tree. 2 The seeds are nearly oval, compressed, rather acute at the 

 apex, and a quarter of an inch long, with a thin black coat produced into a narrow margin, and an 

 embryo with from five to eight cotyledons ; their wings are broadest at the middle, gradually narrowed 

 to the ends, an inch and a quarter long and a third of an inch wide, light brown, lustrous, and marked 

 with longitudinal narrow dark stripes. 



Pinus attenuata grows on dry generally sun-baked mountain slopes and is distributed from the 

 valley of the Mackenzie River in Oregon over the mountains of southwestern Oregon, where at 

 elevations between one and two thousand feet above the sea-level it is most abundant and grows to its 

 largest size, often forming open nearly pure forests over large areas ; it ranges southward along the 

 western slopes of the Cascade Mountains and over the cross ranges of northern California and the 

 western slopes of the Sierra Nevada, growing usually at elevations between fifteen hundred and three 

 thousand feet on dry southern chaparral-covered slopes and ascending on Mt. Shasta to five thousand 

 feet ; over the California coast ranges it is scattered from the Santa Cruz to the southern slopes of the 

 San Bernardino Mountains, 3 where it forms a nearly continuous belt several miles long between two 

 thousand five hundred and four thousand feet above the sea, mingling toward the upper limits of its 

 growth with Pinus Coulteri and Pseudotsuga macrocarpa, and below forming open groves of small 

 stunted trees of loose pyramidal habit, with wide-spreading lower branches. 4 



The wood of Pinus attenuata is light, soft, not strong, brittle, and coarse-grained; it is light 

 brown, with thick white sapwood sometimes slightly tinged with red, and contains very broad rather 



1 Coulter & Rose, Bot. Gazette, xi. 308. tion and perpetuity. (Muir, The Mountains of California, 148, as 



2 The closed cones of this tree, preserving the vitality of the Pinus tuberculata.) 



seeds for years, seem an admirable adaptation to the peculiarly 8 S. B. Parish, Zoe, iv. 351. 



severe conditions of its surroundings, enabling it to survive the 4 Considering the dryness and exposure of the slopes it inhabits, 

 fires which constantly sweep over the dry slopes where alone it Pinus attenuata grows with remarkable rapidity. The log speci- 

 grows. When the trees are killed by fire, as is almost invariably men in the Jesup Collection of North American Woods, in the 

 the case every few years, all the seeds produced during their lives American Museum of Natural History, New York, is twelve and 

 are scattered at the same time over the ground, and, growing a half inches in diameter inside the bark and only fifty-four years 

 rapidly, soon produce an abundant crop of seedlings ; in the same old. The sapwood on this specimen is one and seven eighths inches 

 groves the trees are almost invariably of the same age and size, thick, with seventeen layers of annual growth. Young trees grow- 

 there being no seedlings or younger plants among them to perish ing on the most arid slopes often make terminal shoots from two 

 with the older trees and thus to diminish the chances of reproduc- to three feet long. 



