Outer walls of the leaf-endoderm thick. Cones large, attaining 12 cm. or more in length. Prickles of the cone inconspicuous. Bark-formation late 37. pseudostrobus Bark-formation early 38. Montezumae Prickle 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. Prickle of the cone slender, sometimes deciduous. Cones mostly oblique 41. Lawsonii Cones symmetrical 42. occidentalis Prickles of the cone stout and persistent 43. palustris Spring-shoots multinodal. Resin-ducts internal 44. caribaea. Resin-ducts mostly medial. Prickle of the cone stout 45. taeda Prickle 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 masses, 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 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.