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.

36. PINUS INSULARIS

1837 P. taeda Blanco, Fl. Filip. 767 (not Linnaeus).

1847 P. insularis Endlicher, Syn. Conif. 157.

1854 P. khasiana Griffith, Notul. Pl. Asiat. iv. 18; Icon. Pl.

Asiat. tt. 367, 368.

1868 P. kasya Royle ex Parlatore in DC. Prodr. xvi-2, 390.

Spring-shoots uninodal, glabrous. Leaves from 12 to 24 cm. long, in fascicles of 3, rarely of 2, very slender; resin-ducts external, rarely with a medial duct. Conelets mucronate. Cones from 5 to 10 cm. long, ovate-conic, symmetrical or oblique, tenaciously persistent; apophyses l.u.s.trous, nut-brown, convex or elevated along a transverse keel, the posterior scales of some cones larger and more prominent than the anterior scales, the mucro usually deciduous.

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.

Plate XXIII.

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

[Ill.u.s.tration: PLATE XXIII. P. MERKUSII (198-200), SINENSIS (201-207), INSULARIS (208-210)]

=XI. AUSTRALES=

Pits of the ray-cells small. Leaf-hypoderm biform or variable.

Spring-shoots uninodal in some, multinodal in other species. Cones dehiscent at maturity.

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 alt.i.tude and climate of the western states and Mexico.

Outer walls of the leaf-endoderm thick.

Cones large, attaining 12 cm. or more in length.

p.r.i.c.kles of the cone inconspicuous.

Bark-formation late 37. pseudostrobus Bark-formation early 38. Montezumae p.r.i.c.kle of the cone conspicuous 39. ponderosa Cones small, 7 cm. or less in length 40. teocote Outer walls of the leaf-endoderm thin.

Spring-shoots mostly uninodal.

p.r.i.c.kle of the cone slender, sometimes deciduous.

Cones mostly oblique 41. Lawsonii Cones symmetrical 42. occidentalis p.r.i.c.kles of the cone stout and persistent 43. pal.u.s.tris Spring-shoots multinodal.

Resin-ducts internal 44. caribaea.

Resin-ducts mostly medial.

p.r.i.c.kle of the cone stout 45. taeda p.r.i.c.kle of the cone slender.

Bark-formation late 46. glabra Bark-formation early 47. echinata

37. PINUS PSEUDOSTROBUS

1839 P. pseudostrobus Lindley in Bot. Reg. xxv. Misc. 63.

1839 P. apulcensis Lindley in Bot. Reg. xxv. Misc. 63.

1842 P. tenuifolia Bentham, Pl. Hartw. 92.

1846 P. orizabae Gordon in Jour. Hort. Soc. Lond. i. 237, f.

Spring-shoots uninodal, conspicuously pruinose. Bark-formation late, the cortex of young trees smooth. Leaves in fascicles of 5, sometimes of 6, from 15 to 30 cm. long, drooping; resin-ducts medial, hypoderm variable in amount, often in very large ma.s.ses, the outer walls of the endoderm thick. Conelets mucronate. Cones from 7 to 14 cm. long, ovate or ovate-conic, symmetrical or oblique, deciduous and often leaving a few basal scales on the trees; apophyses rufous or fulvous brown, flat, elevated or, in one variety, prolonged in various degrees, the prolongations nearly uniform or much more prominent on the posterior face of the cone, the mucro usually deciduous.

A species of the subtropical and warm-temperate alt.i.tudes 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 a.s.sociates 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 part.i.tions 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).

Plate XXIV.

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.

[Ill.u.s.tration: PLATE XXIV. PINUS PSEUDOSTROBUS]

38. PINUS MONTEZUMAE

1817 P. occidentalis H. B. & K. Nov. Gen. ii. 4 (not Swartz).

1832 P. Montezumae Lambert, Gen. Pin. ed. 8vo, i. 39, t. 22.

1839 P. Devoniana Lindley in Bot. Reg. xxv. Misc. 62.

1839 P. Hartwegii Lindley in Bot. Reg. xxv. Misc. 62.

1839 P. Russelliana Lindley in Bot. Reg. xxv. Misc. 63.

1839 P. macrophylla Lindley in Bot. Reg. xxv. Misc. 63.

1840 P. filifolia Lindley in Bot. Reg. xxvi. Misc. 61.

1841 P. Sinclairii Hooker & Arnott, Bot. Beechy Voy. 392, t. 93 (as to cone).

1841 P. radiata Hooker & Arnott, Bot. Beechy Voy. 443 (as to leaves).

1847 P. Grenvilleae Gordon in Jour. Hort. Soc. Lond. ii. 77, f.

1847 P. Gordoniana Hartweg in Jour. Hort. Soc. Lond. ii. 79, f.

1847 P. Wincesteriana Gordon in Jour. Hort. Soc. Lond. ii. 158, f.

1847 P. rudis Endlicher, Syn. Conif. 151.

1847 P. Ehrenbergii Endlicher, Syn. Conif. 151.

1858 P. Lindleyana Gordon, Pinet. 229.

1891 P. Donnell-Smithii Masters in Bot. Gaz. xvi. 199.

Spring-shoots uninodal, slightly or not at all pruinose. Bark-formation early, the branches becoming dark and rough. Leaves prevalently in fascicles of 5, but varying from 3 to 8, extremely variable in length, attaining 45 cm. at subtropical levels; resin-ducts medial, hypoderm sometimes uniform, more commonly multiform, the outer walls of the endoderm thick. Conelet mucronate, the p.r.i.c.kle often reflexed. Cones of many sizes, attaining in warm localities 30 cm. in length, ovate-conic or long-conic, symmetrical, often curved, deciduous and often leaving a few scales on the tree; apophyses dull, rarely l.u.s.trous, nut-brown, or of various shades of fuscous brown to nearly black, flat, tumid, pyramidal or sometimes slightly protuberant, the p.r.i.c.kle rarely persistent.

This species ranges from the mountains of northern Durango to the volcanoes of Guatemala, or possibly farther south. It is found at all alt.i.tudes 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 st.u.r.dy Pine and its numberless variations present the most remarkable example of adaptation in the genus. The variations are mostly those a.s.sociated with changes of environment--dimensions of cone and leaf and the number of leaves in the fascicle. These are so accurately correlated with alt.i.tude 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 alt.i.tudes 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 alt.i.tudes 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.