52 SILVA OF NORTH AMERICA. conifer*. 



seasons, although some of them frequently remain on the branches until their twelfth year. The 

 staminate flowers are oval, dark red, and about a quarter of an inch long, with anthers terminating in 

 knobs or in minute teeth, and are usually surrounded by six involucral bracts. The pistillate flowers 

 are lateral and oval, with thick rounded apiculate scales, and are raised on short stout peduncles 

 covered by ovate lanceolate light chestnut-brown bracts. In the autumn the young cones are oblong, 

 erect, and about half an inch long, and, beginning to grow very early the following spring, they are 

 nearly half grown when the flowers open in May ; at maturity they are from one and a half to two and 

 a half inches in length, somewhat less in breadth, and bright green, with concave scales rounded at the 

 apex, the exposed portion being much thickened, four-angled, and gradually narrowed into a prominent 

 knob terminating in a truncate or slightly concave umbo furnished with a minute incurved tip ; only a 

 few of the middle scales, which are often three quarters of an inch across, are fertile ; the others are 

 much smaller, and those below the middle, gradually decreasing in size and remaining closed, form a 

 broad base to the mature cone; after opening and shedding their seeds the cones become light 

 chestnut-brown and lustrous, giving a reddish tone to the tree when they are abundant. The seeds are 

 oblong, full and rounded at the base, acute at the apex, dark red-brown and rounded on the lower side, 

 slightly compressed and pale yellow-brown on the upper side, about five eighths of an inch long and a 

 quarter of an inch broad, with a thin brittle shell, an oily resinous albumen, and an embryo with from 

 seven to ten cotyledons ; their wings are membranaceous, light brown, from one third to one half of an 

 inch wide, and remain attached to the scales after the seeds fall. 



Pinus monophylla inhabits dry gravelly slopes and mesas, and is distributed from the western 

 base of the Wasatch Mountains in Utah westward over the mountain ranges of the Great Basin, on 

 which it usually forms, above elevations of six thousand feet, open forests with Juniperus Utahensis, 

 ■ generally ascending to higher altitudes than that tree ; x on the eastern slopes of the southern Sierra 

 Nevada it constitutes a nearly continuous belt between six and eight thousand feet above the sea, and 

 crossing the range to the head-waters of King's River is common at an elevation of five thousand 

 five hundred feet on the north wall of the canon and on Paradise fork of the south fork at heights 

 of between six and seven thousand feet. 2 In California it is also abundant on the desert mountains 

 of the southeast, usually at elevations of between five and seven thousand feet and mingled with 

 Junipers below and with JPinus aristata above, and ranges southwestward to the northern slopes of 

 the San Bernardino 3 and San Jacinto Mountains, 4 crossing the southern boundary of the state into 

 Lower California and maintaining on the slopes from the central table-land of the peninsula to the 

 plains of the Colorado Desert a precarious foothold, 5 and to the Tehachapi Mountains, from which, 

 along the sides of the canon leading from the Tehachapi Valley to the Mohave Valley, it descends to 

 three thousand seven hundred feet above the sea-level ; it also dots the northern slopes of the San 

 Emigdio Mountains, 6 at elevations of from six thousand to seven thousand feet, mixed with Juniperus 

 Californica, and extends to the San Rafael Mountains, growing here down to elevations of three 

 thousand feet. 7 It is common on the mesas of southern Utah ; in Arizona it occupies a broad zone 

 on the western slopes of the Virgin Mountains, grows in open forests along the southern rim of the 

 Colorado plateau, and forms, on the Bradshaw, Mazatzal, and Mogollon Mountains south of the plateau, 



in this genus of a single cylindrical leaf occupying the apex of a 3 S. B. Parish, Zoe, iv. 335. 



branchlet is explained by Masters (Ann. Bot. ii. 124), who, in study- 4 Pinus monophylla was found near the head of the San Felipe, on 



ing the early development of the leaf-bud of Pinus monophylla, the edge of the Colorado Desert, California, by Mr. T. S. Brande- 



f ound always two foliar tubercles, one of them usually overpassing gee in 1894. 



the other and obliterating all trace of a. second leaf. (See, also, 5 Orcutt, Garden and Forest, v. 184. 



Bertrand, Ann. Sci. Nat. se"r. 5, xx. 102, t. 9, f. 5, 6. — Coulter & 6 Teste Miss Alice Eastwood. 



Rose, Bot. Gazette, xi. 302.) 7 Pinus monophylla was collected on the San Rafael Mountains, 



1 Sargent, Am. Jour. Sci. ser. 3, xvii. 419 (The Forests of Central a part of the great cross range which divides the central valley of 

 Nevada). California from the southwestern part of the state, in May, 1894, 



2 Teste John Muir. by Dr. F. Franceschi. 



