56 BILVA OF NORTH AMERICA. conifers. 



summer are from a quarter of an inch to an inch and a half long, almost as broad, and light green, 

 with concave scales rounded at the apex, the exposed portion being much thickened, conspicuously 

 transversely keeled, and narrowed into a four-angled central knob which terminates in the large light 

 brown slightly concave umbo furnished with a minute incurved tip ; only the central scales, which are 

 about half an inch broad, are fertile ; the others are smaller and below the middle decrease rapidly in 

 size, and, remaining closed, form a broad base to the mature cone, which becomes light brown and lustrous 

 in its exposed parts, the base of the scales being dull light red, while the umbos are usually covered with 

 a thick coat of resin. The seeds are ovate, acute, full and rounded at the base, semicylindrical or more 

 or less compressed by pressure against the bracts of the scales above them, dark red-brown on the lower 

 and lio-ht orange-color or yellow on the upper side, and about half an inch long, with a thin brittle 

 shell, an oily resinous albumen, and an embryo with from seven to ten cotyledons ; their wings are 

 membranaceous, light reddish brown, about an eighth of an inch wide, and when the seeds fall remain 

 attached to the cone-scales. 1 



Pinus edulls is distributed from the eastern foothills of the outer ranges of the Rocky Mountains 

 of Colorado south of the divide between the waters of the Platte and the Arkansas Rivers, usually 

 forming with Juniperus monosperma and Pinus ponderosa open forests at elevations between six 

 and eight thousand feet above the sea-level, westward through Colorado to the eastern borders of Utah 

 and to the valley of Little Snake River in southwestern Wyoming ; at the head of the Arkansas, at 

 elevations between eight and nine thousand feet above the sea, it covers the broad Buena Vista 

 valley with an open forest in which Pinus ponderosa is its principal associate ; mixed with Juniperus 

 Utahensis it dots the hills and table-lands of western Colorado, descending in the valleys of White and 

 Grand Rivers to elevations of less than five thousand feet above the sea-level ; it ranges southward over 

 the Rocky Mountains of New Mexico to the Guadalupe, Limpio, Organ, and Chicos Mountains of 

 western Texas, and grows also in Texas on the bluffs at the great bend of the Rio Grande, on the 

 forks of the Nueces River, and on the border of the high plateau of the Staked Plain ; 2 it extends 

 southward over the mountains of northern Mexico and westward to northern and central Arizona, 

 where with Junipers it abounds on the Colorado plateau, and on the Bradshaw, Mogollon, Pinal, Super- 

 stition, Caliuro, and other mountain ranges south of it, 3 forms a well marked forest belt at elevations 

 between six and seven thousand feet above the sea and below the forests of Pinus ponderosa? 



The wood of Pinus edulis is light, soft, not strong, brittle, close-grained, and durable in contact 

 with the soil ; it is pale brown, with thin nearly white sapwood, and contains thin inconspicuous bands 

 of small summer cells, few resin passages, and many obscure medullary rays ; the specific gravity of 

 the absolutely dry wood is 0.6388, a cubic foot weighing 39.81 pounds. It is largely used for fuel, 

 for fencing, and in the manufacture of charcoal for smelting purposes, and in western Texas is 

 occasionally sawed into lumber. 5 



The sweet edible seeds form an important article of food among Indians and Mexicans, 6 and are 



1 Some good observers have considered Pinus edulis as a two- Utah which I have been able to examine appear distinctly to be- 



leaved form of Pinus monophylla, and that the two forms are con- long to Pinus monophylla, which frequently produces leaves in 



nected by trees in southern Utah with foliage about equally divided clusters of two. (See Hooker f. Gard. Chron. n. ser. xxvi. 136.) 



between the one and the two-leaved clusters. (See Newberry, Bull. 2 Havard, Proc. U. S. Nat. Mus. viii. 503. 



Torrey Bot. Club, xii. 50 ; xiii. 183. — Meehan, Bull. Torrey Bot. 8 Tourney, Garden and Forest, x. 152. 



Club, xii. 81. — M. E. Jones, Zoe, ii. 251 ; Hi. 307.) 4 Merriam, North American Fauna, No. 3, 122. 



But in spite of the general resemblance in the habit and the 6 Pinus edulis grows slowly. The log specimen in the Jesup 



similarity in leaf structure of the two trees, Pinus edulis, in its Collection of North American Woods in the American Museum 



much more slender less spinescent usually shorter and darker of Natural History, New York, is six and three quarters inches 



green leaves sometimes borne in clusters of three, and in its in diameter inside the bark and has three hundred and sixty-nine 



smaller cones, appears to differ sufficiently from Pinus monophylla, layers of annual growth, with twenty-seven layers of sapwood 



which inhabits more arid regions, to justify their specific separa- which is half an inch in thickness. 



tion. I have never seen the two forms growing together or passing 6 Newberry, Popular Science Monthly, xxxii. 35 (Food and Fibre 



one into the other, and all the two-leaved specimens from southern Plants of the North American Indians). 



