36 SILVA OF NORTH AMERICA. conifers. 



ovate-lanceolate loosely imbricated light chestnut-brown scales scarious on the margins, the terminal 

 bud being about half an inch long and a quarter of an inch broad and nearly twice as large as the 

 lateral buds. The leaves are borne in five-leaved clusters, and during the winter are inclosed in minute 

 compressed dark green buds covered with pale scurfy pubescence. The bud-scales when fully grown 

 are thin, white and lustrous, or pale chestnut-brown, and form a close narrow sheath about three 

 quarters of an inch long, and early deciduous. The leaves are stout, rigid, sharp-pointed with callous 

 tips, entire, or rarely sparingly serrate toward the apex, dark green, and usually about two inches long, 

 but vary from an inch and a half to three inches in length ; they are marked with from one to four 

 rows of ventral stomata, and contain a single fibro-vascular bundle and two dorsal and occasionally also 

 one ventral resin duct surrounded by thin-walled strengthening cells ; l they form dense tufts at the 

 ends of the branches, and mostly fall during their fifth and sixth years. The staminate flowers, which 

 are borne in short spikes, are oval and about half an inch long, with reddish anthers tipped with short 

 spur-like crests, and are surrounded by eight or nine involucral bracts. The pistillate flowers are 

 subterminal, clustered, about half an inch long, bright red-purple, and nearly sessile or short-stalked, their 

 thick peduncles being covered with ovate acute persistent chestnut-brown bracts scarious on the margins 

 and from one third to nearly one half an inch in length. In the autumn the young cones are erect, 

 from three quarters of an inch to an inch long, about half an inch broad, and light reddish brown ; 

 they become horizontal, and grow rapidly during the following spring, and when the flowers open, 

 which is late in June, or at the north early in July, they have attained about two thirds of their full 

 size ; and when fully grown in September they are oval or subcylindrical, horizontal and subsessile, 

 or slightly declining on stout peduncles sometimes half an inch in length, light green, from three to 

 ten inches lon^ 2 and about an inch and a half wide, with thick scales rounded at the broad or somewhat 

 narrowed apex, which is occasionally slightly reflexed, and is tipped with a thickened dark umbo, 

 the lower sterile scales being narrow and strongly reflexed ; the cones ripen and shed their seeds in 

 September ; the exposed portions of the scales then turn light brown, and the others dull light red, 

 most of the cones falling from the branches late in the same autumn. The seeds are oval, compressed, 

 and from one third to one half of an inch in length, and are covered by a dark red-brown coat mottled 

 with black, and produced into a narrow margin ; their wings are thin, dark reddish brown, and about 

 one twelfth of an inch wide, and generally remain attached to the scales when the seeds fall ; the 

 cotyledons vary from six to nine in number. 



The Rocky Mountain White Pine is distributed along the eastern base of the continental divide 

 from Bow River in Alberta, where it grows on the river cliffs from near Calgary to Morleyville, 3 

 southward to western Texas, where it occurs on the Guadalupe and Limpio Mountains ; 4 it ranges 

 westward, usually at elevations of from five to ten thousand feet above the sea-level, over the mountains 

 of Wyoming, Montana, Colorado, Utah, Nevada, and southwestern California, where it has been found 

 on the Inyo and Panamint Mountains growing with Pinus aristata, 5 to the eastern slopes of the 

 Sierra Nevada Mountains, where it is rare from Mono Pass east of the Yosemite Valley at elevations of 

 from eight to nine thousand feet above the sea southward to Kearsarge Pass, crossing the Sierras to 

 the south side of the canon of the south fork of King's River, where it occurs at heights of from ten 

 thousand five hundred to nearly twelve thousand feet above the sea ; 6 it spreads over the mountain 



1 Coulter & Rose, Bot. Gazette, xi. 261. tains, varies greatly in the size of its cones and in the thickness of 



2 The longest cones are produced by trees growing on the San its leaves. It is probably tbe large-coned southern form which is 

 Francisco Peaks of northern Arizona at elevations of about eight most common on the mountains of eastern Arizona and of New 

 thousand feet above the sea-level and on the mountains of southern Mexico, and which has sometimes been referred to Pinus strohir 

 Arizona (the var. macrocarpa of Engelmann and the var. megalo- formis. 



carpa of Sudworth). The same trees, however, bear cones varying 3 Macoun, Cat. Can. PI. 465. 



from four to ten inches in length (see plate dxlvii.), and although 4 Havard, Proc. U. S. Nat. Mus. viii. 503. 



the leaves on this form are slightly more slender and occasionally 5 Merriam, North American Fauna, No. 7, 340 {Death Valley 



somewhat serrulate toward the apex, it can hardly be considered a Exped. ii.). 



botanical variety, as Pinus flexilis, in the northern Rocky Moun- 6 Teste John Muir. 



