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.
[Illustration: PLATE XXIV. PINUS PSEUDOSTROBUS]
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.
