The Genus Pinus Part 15

Plate XXV. (Cones and leaves much reduced.)

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.

[Ill.u.s.tration: PLATE XXV. PINUS MONTEZUMAE]

39. PINUS PONDEROSA

1836 P. ponderosa Douglas ex Lawson's Agric. Man. 354.

1847 P. Benthamiana Hartweg in Jour. Hort. Soc. Lond. ii. 189.

1848 P. brachyptera Engelmann in Wislizenus, Tour Mex. 89.

1848 P. macrophylla Engelmann in Wislizenus, Tour Mex. 103 (not Lindley).

1853 P. Jeffreyi Balfour in Bot. Exp. Oregon, 2, f.

1854 P. Engelmanni Carriere in Rev. Hort. 227.

1855 P. Beardsleyi Murray in Edinb. Phil. Jour. ser. 2, i. 286, t. 6.

1855 P. Craigana Murray in Edinb. Phil. Jour. ser. 2, i. 288, t. 7.

1858 P. Parryana Gordon, Pinet. 202 (not Engelmann).

1859 P. deflexa Torrey in Emory's Rep. ii. 1, 209, t. 56.

1878 P. arizonica Engelmann in Wheeler's Rep. vi. 260.

1889 P. latifolia Sargent in Gar. & For. ii. 496, f. 135.

1894 P. apacheca Lemmon in Erythea, ii. 103, t. 3.

1897 P. Mayriana Sudworth in Bull. 14, U. S. Dept. Agric. 21.

1897 P. scopulorum Lemmon in Gar. & For. x. 183.

1900 P. peninsularis Lemmon, W. Am. Conebear. 114.

Spring-shoots uninodal, sometimes pruinose. Bark-formation early. Leaves prevalently in fascicles of 3, but varying from 2 to 5 or more, from 12 to 36 cm. long; resin-ducts medial, hypoderm uniform or multiform, outer walls of the endoderm thick. Conelet mucronate, the mucro often reflexed. Cones from 8 to 20 cm. long, ovate-conic, symmetrical, deciduous and usually leaving a few basal scales on the tree; apophyses tawny yellow to fuscous brown, l.u.s.trous, elevated along a transverse keel, sometimes protuberant and reflexed, the umbo salient and forming the base of a pungent, persistent p.r.i.c.kle.

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 a.s.sociated 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 pa.s.sing 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.

Plate XXVI.

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.

[Ill.u.s.tration: PLATE XXVI. PINUS PONDEROSA]

40. PINUS TEOCOTE

1830 P. teocote Schlechtendal & Chamisso in Linnaea, v. 76.

Spring-shoots uninodal, or sometimes multinodal. Leaves prevalently in fascicles of 3, but varying from 3 to 5, from 10 to 20 cm. long; resin-ducts medial, sometimes with an internal duct, hypoderm biform, endoderm with thick outer walls. Conelets mucronate. Cones usually very small, from 4 to 6 cm. long, but with a larger varietal form, ovate to long-conic, symmetrical; apophyses nut-brown, flat or tumid, the mucro usually deciduous.

This species grows at temperate alt.i.tudes from Chiapas to Nuevo Leon, a.s.sociated 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.

Plate XXVII.

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.

41. PINUS LAWSONII

1862 P. Lawsonii Roezl ex Gordon, Pinet. Suppl. 64.

1905 P. Altamirani Shaw in Sargent, Trees & Shrubs, i. 209, t. 99.

Spring-shoots conspicuously pruinose, uninodal or not infrequently multinodal. Leaves in fascicles of 3, 4 or 5, not exceeding 24 cm. in length; resin-ducts internal, often with one or two medial ducts, hypoderm biform, endoderm usually with thin outer walls. Conelets mucronate. Cones from 5 to 7 cm. long on pliant peduncles, ovate or ovate-conic, oblique or sometimes symmetrical, deciduous, or persistent with a weak hold on the branch; apophyses nut-brown, flat or tumid, often protuberant on the posterior face of the cone, the umbo usually large and salient, forming a rounded b.u.t.ton-like projection, on which the mucro is wanting.

A subtropical species of central and western Mexico, growing alone or a.s.sociated with P. oocarpa, P. Pringlei and the subtropical forms of P. Montezumae and P. pseudostrobus. It is recognized among its a.s.sociate 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.

Plate XXVII.

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

[Ill.u.s.tration: PLATE XXVII. P. TEOCOTE (235-238), LAWSONII (239-241)]

42. PINUS OCCIDENTALIS

1788 P. occidentalis Swartz, Nov. Gen. & Sp. Pl. 103.

1862 P. cubensis Grisebach in Mem. Am. Acad. ser. 2, viii. 530.

1880 P. Wrightii Engelmann in Trans. Acad. Sci. St. Louis, iv. 185.

Spring-shoots uninodal, pruinose. Leaves in fascicles of 2 to 5, from 15 to 22 cm. long; resin-ducts internal, hypoderm biform, endoderm with thin outer walls. Conelets erect, aristate. Cones from 5 to 8 cm. long, reflexed, ovate, symmetrical, deciduous; apophyses nut-brown, l.u.s.trous, flat or tumid, the umbo often thin and, together with the slender p.r.i.c.kle, bent sharply downward.

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.

Plate XXVIII.

Fig. 247, Cone. Fig. 248, Conelet and enlarged aristate scales. Fig.

249, Magnified sections of two leaves and more magnified dermal tissues.

43. PINUS PAl.u.s.tRIS

1768 P. pal.u.s.tris Miller, Gard. Dict. ed. 8.

1810 P. australis Michaux f. Hist. Arbr. Am. i. 64, t. 6.

Spring-shoots uninodal, rarely multinodal. Buds peculiarly large, white, and conspicuously fringed with the long free cilia of the bud-scales.

Leaves in fascicles of 3, from 20 to 45 cm. long, rigid; resin-ducts internal, hypoderm biform, endoderm with thin outer walls. Conelets short-mucronate. Cones from 15 to 20 cm. long, narrow, tapering from a rounded base to a blunt point, symmetrical, deciduous and usually leaving a few scales on the tree; apophyses dull nut-brown, elevated along a transverse keel, the umbo salient and forming the broad base of a small persistent p.r.i.c.kle.

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.