P. montana grows as a bush or as a small tree, the two forms often associated. It ranges from central Spain through the Pyrenees, Alps and Apennines to the Balkan Mountains, associated with P. cembra at higher, with P. sylvestris at lower altitudes. It grows indifferently in bogs and on rocky slopes. Its dwarf form, under the name of the Mugho Pine, is extensively cultivated as a garden ornament.

On the differences of the cone this species has been divided into three subspecies: uncinata, with an oblique cone and protuberant apophyses; pumilio, with a symmetrical cone and an excentric umbo; mughus, with a symmetrical cone and a concentric umbo. Other segregations based on the degree of development of the apophysis and on the size and color of the cone, have received names of four or even five terms—Pinus montana pumilio applanata—or Pinus montana uncinata rostrata castanea etc., etc. These elaborations may be seen in the Tharand Jahrbuch of 1861, p. 166, and with them appear also Hartig's specifications of 60 forms of this species, each dignified with a Latin name.

Fig. 186, Cone of var. uncinata. Figs. 187, 188, Cones. Fig. 189, Leaf-fascicles, magnified leaf-section and more magnified dermal tissues of the leaf. Fig. 190, Tree and dwarf-form of the Pyrenees.

This Pine is known to me through Mayr's description and a single dried specimen. The smooth cortex of young trees distinguishes it from all other east-Asiatic Hard Pines. Mayr includes under this species the Pine of Hong Kong. But in this he must be mistaken, for there is no species yet found in China that agrees with the description of P. luchuensis.

Fig. 191, Cone. Fig. 192, Leaf-fascicle and magnified leaf-section.

The Black Pine of Japan has been cultivated for centuries, and by skillful Japanese gardeners has been trained into dwarf and other curious forms. It is hardy in cold-temperate climates. It is distinct from P. densiflora by the medial ducts of its leaf, from P. nigra by the fewer, larger, brown scales of its cone, and from P. resinosa by the armature of its conelet. It appears in most determinations of Chinese collections, but there is no Chinese Pine with the white buds and the medial leaf-ducts of this species.

Fig. 196, Two cones. Fig. 197, Leaf-fascicle and magnified leaf-section.

A valuable tree unequally distributed over the mountain slopes of central and southern Europe and Asia Minor. The typical form, under the name of the Austrian Pine, is a familiar exotic of the Middle and Eastern States of America. As Mathieu states (Flore Forest., ed. 4, 597), this species is quite constant in cone and bark. It may be added that the anatomy of the leaf is also constant, while the dimensions of both leaf and cone present no unusual variations. The varieties generally accepted are founded on the habit of the tree, a character of forestal or horticultural rather than of botanical importance.

Fig. 193, Two cones. Fig. 194, Leaf-fascicle and magnified leaf-section. Fig. 195, Magnified dermal tissues of the leaf.

Of the habit of this Pine I know nothing. As a species it is very clearly defined by its peculiar cone and leaf-section. It grows in the Philippines, Sumatra, Lower Burmah and western Indo-China. In my specimen the pits of the ray-cells of the wood are both large and small. In this particular it may belong in either of two groups of species. Its uniform leaf-hypoderm associates it with this group or with P. halepensis of the Insignes. I have assumed the cone to be dehiscent at maturity and have placed it with the Lariciones, but if further information shows the cone to be serotinous, this species should be transferred to the serotinous group.

Fig. 198, Cone. Fig. 199, Magnified sections of two leaves. Fig. 200, Leaf-fascicle.

A tree of cold-temperate and subalpine levels, growing on the mountains of central and western China, and at lower altitudes in the north and in Corea. It is recognized by its tenaciously persistent cones with a remarkable change in color. It is constantly confused with P. Thunbergii and P. densiflora, neither of which grows spontaneously in China. From the former it differs in leaf-section and bud (the bud of P. sinensis is never white), from the latter in the lustre and the color variation of its cone, and from both in the frequent obliquity of its cone and in the frequent presence of trimerous leaf-fascicles.

Of the two varieties of this species, densata and yunnanensis (Shaw in Sargent, Pl. Wilson. ii. 17), the former represents the extreme oblique form of cone, the latter represents the longest dimensions of cone and leaf. The effect of environment on this species can be seen in figs. 202, 203, from a lower slope and rich soil, and fig. 204, from a high rocky ledge in the same locality.

Fig. 201, Cone of var. densata. Fig. 202, Cone of var. yunnanensis. Fig. 203, Leaf-fascicle and magnified leaf-section of var. yunnanensis. Fig. 204, Cone and leaf-fascicle from a rocky ledge. Fig. 205, Cone, leaf-fascicle and magnified leaf-section of the typical form. Fig. 206, Seeds. Fig. 207, Conelet and its enlarged scale.

A species of the Philippines and of northern Burmah. In both countries it is locally exploited for wood and resin. It differs from the common form of P. sinensis by its much longer leaves, and from its var. yunnanensis, which it more resembles, by its much more slender and pliant leaves. Moreover its cone, so far as I can learn, is not yellow at maturity, but brown.

Figs. 208, 209, Three cones. Fig. 210, Leaf-fascicle and magnified leaf-section.

This group combines the dehiscent cone of the Lariciones with the wood-anatomy of the serotinous Pines. Also the multinodal spring-shoot first appears here and is gradually developed among the species, absent in Nos. 37-39, sometimes present in Nos. 40-43, and prevalent in Nos. 44-47.

All the species are of the Western Hemisphere, and among them may be found the biform hypoderm of the leaf, the internal resin-duct, and the total absence of external resin-ducts, characters common in American Hard Pines. The eastern species are quite constant in their characters and present no varietal forms; the western species, on the other hand, are very variable. This difference may be due to the even level and slight climatic differences of the Atlantic states and to the remarkable diversity of altitude and climate of the western states and Mexico.

A species of the subtropical and warm-temperate altitudes of Mexico and Central America. Its range includes both eastern and western slopes of the northern plateau. Its northern limit is in Nuevo Leon, and it probably reaches in Nicaragua the southern limit of pines in the Western Hemisphere. It is distinguished from all its associates by the smooth gray trunk of the young trees, by their long internodes, and by their drooping gray-green foliage.

Some cones of this species develop protuberances of all degrees of prominence up to the curious cone collected in Oaxaca by Nelson (var. apulcensis, Shaw, Pines Mex. t. 12, fig. 8). There is also a remarkable difference in the amount of leaf-hypoderm. On many trees of the western part of the range this tissue forms septa across the green mesophyll. Such partitions are sometimes met in other species, P. Pringlei or P. canariensis, where the hypoderm is abundant. But in P. pseudostrobus they appear in some leaves of weak, as well as of strong hypoderm (var. tenuifolia, Shaw, Pines Mex. t. 13, ff. 2, 4, 5, 7, 8).

Fig. 211, Cone. Fig. 212, Two cones of var. tenuifolia. Figs. 213, 214, Two cones of var. apulcensis. Fig. 215, Magnified section of 3 leaves of var. tenuifolia. Fig. 216, Magnified section of 2 leaves of the species. Fig. 217, Bud destined to produce staminate flowers. Fig. 218, Ten-year old branch showing smooth cortex. Fig. 219, Young and mature trees in open growth.

This species ranges from the mountains of northern Durango to the volcanoes of Guatemala, or possibly farther south. It is found at all altitudes where Pines can grow except on the tropical levels of Guatemala. Its more hardy forms have been successfully grown in the milder parts of Great Britain and northern Italy. It is felled for lumber in many parts of Mexico.

This sturdy Pine and its numberless variations present the most remarkable example of adaptation in the genus. The variations are mostly those associated with changes of environment—dimensions of cone and leaf and the number of leaves in the fascicle. These are so accurately correlated with altitude and exposure, and are so imperceptibly graded, that no specific segregations among them have yet been successfully established.

The type-specimen figured by Lambert does not show the longest cone and leaf of this species. They are better represented by specimens which have been named P. filifolia. Such dimensions prevail in subtropical localities. At temperate altitudes these dimensions are much reduced, but here are found a longer form of cone and leaf (var. Lindleyi, Loudon) and a shorter form (var. rudis, Shaw). At still higher altitudes and up to the timber-limit the var. Hartwegii, Engelmann, with short leaves and a small nearly black cone is found. Among these varieties there is no such sharp distinction as these definitions imply. All dimensions of fruit and foliage and the various brown and black shades of the cone blend into each other through endless intergradations. A monograph of this species, by one who could devote some years to it on the superb volcanoes and in the delightful climates where this tree abounds, would be a valuable contribution to science.

Fig. 220, Cone and leaves of Lambert's plate. Figs. 221, 222, Longer cones and leaves of the species. Fig. 223, Cone and leaves of var. Lindleyi. Fig. 224, Cones and leaves of var. rudis. Fig. 225, Cone and leaves of var. Hartwegii. Fig. 226, Magnified leaf-sections. Figs. 227, 228, Two forms of the dermal tissues of the leaf, magnified. Fig. 229, Habit of the tree.

This species ranges from southern British Columbia over the mountains between the Pacific and the eastern foot-hills of the Rocky Mountains, including the Black Hills of South Dakota, to the northeastern Sierras of Mexico, to northern Jalisco and Lower California, forming, in many localities, large forests and furnishing the best Hard Pine timber of the western United States. It attains its best growth on the Sierras of California and is, next to P. Lambertiana, the tallest of the Pines.

Like P. Montezumae, and under like influences, it shows much dimensional variation, and the leaf-fascicles are heteromerous, with the larger number in the southern part of its range. Many authors consider the variety Jeffreyi Vasey to be a distinct species; but here, it seems to me, too much importance is attached to the pruinose branchlet, clearly a provision against transpiration and associated rather with a dry environment than with a species. Most observers discover many intermediate forms between this variety and the species. The var. scopulorum Engelm. is the Rocky Mountain form with leaves in 2's and 3's and with small cones passing into P. arizonica, Engelm., a more southern form with small cones and leaves in fascicles of 3 to 5. The var. macrophylla (Shaw, Pines Mex. 24), in addition to its long and stout leaves, bears a cone with protuberant apophyses, somewhat comparable to the intermediate forms of P. pseudostrobus var. apulcensis Shaw (l. c.). Fascicles of 6 and 7 leaves are sometimes found, and specimens that I have collected in Sandia, Durango (issued by Pringle, through a misunderstanding, under the name P. Roseana, ined.) show such fascicles on the fertile branches.

Fig. 230, Cone and seed of var. Jeffreyi. Fig. 231, Cone of var. macrophylla. Fig. 232, Cone of var. scopulorum. Fig. 233, Magnified leaf-section and cells of leaf-endoderm. Fig. 234, Magnified dermal tissues of the leaf, showing uniform and multiform hypoderm.

This species grows at temperate altitudes from Chiapas to Nuevo Leon, associated with temperate Mexican species such as P. patula, P. leiophylla and others, and is easily recognized by its small cone. The variety with a larger cone (var. macrocarpa, Shaw, Pines Mex. t. 10) I have found growing in mixed groves of P. teocote and P. leiophylla. It resembles the latter in cone and leaf, but lacks the peculiar character that distinguishes P. leiophylla from all other Mexican species—the triennial cone. Some of the specimens of Hartweg No. 441 belong here, as well as Pringle's specimens, Nos. 10013, 10018, distributed as P. eslavae, ined.

Fig. 235, Two cones of the species and the larger cone of the variety. Fig. 236, Leaf-fascicle and magnified sections of two leaves. Fig. 237 a, Dermal tissues of the leaf magnified; b, magnified cells of the leaf-endoderm. Fig. 238, Habit of the tree.

A subtropical species of central and western Mexico, growing alone or associated with P. oocarpa, P. Pringlei and the subtropical forms of P. Montezumae and P. pseudostrobus. It is recognized among its associate species by its conspicuously glaucous foliage. The cone is very variable on trees of the same grove, both in size and in the protuberance of its apophyses. Gordon's specimen in the Kew herbarium consists of a single detached cone and a few leaves. The leaves differ from all that I have examined in showing thick-walled endoderm cells, but the cone corresponds with many of my own collection.

Fig. 239, Three cones. Fig. 240, Leaf-fascicle and magnified leaf-section. Fig. 241, Magnified cells of the leaf-endoderm.

This species is confined to San Domingo, Hayti and eastern Cuba. Its erect conelet and reflexed cone distinguish it from P. caribaea, which has both its conelet and cone reflexed. Moreover the conelet is usually, perhaps always, subterminal in P. occidentalis.

Fig. 247, Cone. Fig. 248, Conelet and enlarged aristate scales. Fig. 249, Magnified sections of two leaves and more magnified dermal tissues.

Its thin sap-wood, its very strong heavy wood of large dimensions with abundant resin of excellent quality make this the most valuable species of the genus. It ranges over the sandy plain that borders the Atlantic and the Gulf of Mexico, from southeastern Virginia to eastern Texas. The northern limit is approximately the centre of the Southern and Gulf States, with a northern extension in Alabama to the base of the Appalachian Mountains and to northwestern Louisiana. Its southern limit lies near the centre of the Florida peninsula.

Among its associates this species is recognized by its large white fringed bud and its elongated cone. Its leaves attain, on vigorous trees, the maximum length among Pines, but on most trees the leaves do not differ in length from the longer forms of those of P. caribaea or P. taeda. A peculiarity, which it shares with P. caribaea, is the deciduous scaly bark of mature trees, constantly falling away in thin irregular scales.

Figs. 242, 243, Cones and seed. Fig. 244, Bud. Fig. 245, Magnified leaf-section. Fig. 246, Magnified cells of the leaf-endoderm. The dermal tissues of fig. 249 also apply to this species.

The northern limit of the range of P. caribaea extends from the coast of southeastern S. Carolina through southeastern Georgia and southern Alabama to southeastern Louisiana. It is associated with P. palustris, taeda, serotina, echinata and glabra in this part of its range. It continues through Florida, where it encounters P. clausa. On the Bahamas it is the only Pine. On the Isle of Pines it finds in P. tropicalis another associate. It also grows in Honduras and Guatemala. The wood and resin of this species are of such excellent quality that no commercial distinction is made between P. caribaea and P. palustris.

Fig. 250, Cone from the Isle of Pines. Fig. 251, Small form of cone. Fig. 252, Large form of cone and binate leaf-fascicle. Fig. 253, Conelet. Fig. 254, Magnified sections of leaves from binate and ternate fascicles. Fig. 255, Habit of the tree, contrasted with a tree of P. palustris in the middle-distance.

The species ranges from southern New Jersey to southern Arkansas, Oklahoma, eastern Texas and southwestern Tennessee, but does not occur in the lower half of the Florida peninsula. It is an important timber-tree, manufactured into all descriptions of scantlings, boarding and finish, but the wood is of various qualities. It may be recognized by the spine of its cone in both years of growth. Excepting the formidable armature of the cone of P. pungens, the spines are the strongest and most persistent of all the species of eastern North America.

Fig. 264, Cone. Fig. 265, Leaf-fascicle. Fig. 266, Magnified leaf-section. Fig. 267. Magnified scales of the conelet.

A tree that sometimes attains important dimensions, growing singly or in small groves from the neighborhood of Charleston, S. C., to eastern Louisiana and central Mississippi, most abundant in a strip of territory on either side of the northern boundary of Florida. Among the Pines of the southeastern United States it is the only species with late bark-formation, and is therefore easily identified.

Fig. 256, Cone. Fig. 257, Enlarged scale of the conelet. Fig. 258, Leaf-fascicle and magnified leaf-section. Fig. 259, Dermal tissues of the leaf magnified, with a double row of hypoderm cells.

This species ranges from southeastern New York to northern Florida, to West Virginia and eastern Tennessee, and through the Gulf States to eastern Louisiana, eastern Texas, southern Missouri and southwestern Illinois. It is extensively manufactured into material of all kinds that enters into the construction of buildings. It differs from P. virginiana in its longer leaves, brittle branches, and much greater height, from P. glabra in its rough upper trunk, and from both by the frequent presence of trimerous leaf-fascicles.

Of the six or seven pines of the southeastern United States, this species covers a larger area and ascends the slopes of the Alleghany Mountains far enough to meet the northern species, P. virginiana, P. rigida, and P. strobus. Unlike the western members of this group, P. echinata and its associates are not variable. Their characters are singularly constant, as their limited synonymy and total lack of varietal names attest.

Fig. 260, Cone. Fig. 261, Leaf-fascicle and magnified leaf-section from a ternate fascicle. Fig. 262, Magnified leaf-section from a binate fascicle. Fig. 263, Multinodal branchlet bearing lateral and subterminal conelets and a ripe cone. Figs. 257, showing mucronate scales of the conelet, and 259, showing dermal tissues of the leaf, are applicable also to this species.