This species grows at subtropical or warm-temperate altitudes in Mexico, from Oaxaca through the central and western states to southern Arizona and New Mexico. As it approaches the northern part of its range the leaves become thicker and more rigid and the number in the fascicle is reduced to 3 or 4 (var. chihuahuana, Shaw, Pines Mex. 14). Like P. rigida it sprouts freely along the branches and trunk, and stumps of felled trees put out shoots in great numbers. The species is easily recognized by the deciduous sheath and triennial cone. Plate XVI. Fig. 151, Branch with fruit of first, second and third years. Fig. 152, Leaf-fascicles. Fig. 153, Magnified leaf-section of the species. Fig. 154, Magnified leaf-section of the variety. 21. PINUS LUMHOLTZII 1894 P. Lumholtzii Robinson & Fernald in Proc. Am. Acad. xxx. 122. Spring-shoots uninodal, sometimes multinodal. Leaves in fascicles of 3, the sheath deciduous, from 20 to 30 cm. long, absolutely pendent; resin-ducts medial and internal. Conelets subterminal, or lateral and subterminal, mucronate. Cones not exceeding 7 cm. in length, symmetrical, pendent on slender peduncles, ovate-conic, early deciduous; apophyses sublustrous, nut-brown, tumid at the margins, flat on the surface, the umbo large, the mucro rarely persistent. A remarkable Pine with long pendent bright green foliage, confined to the western states of Mexico and ranging on the mountains from southern Jalisco to the latitude of the city of Chihuahua. Each season's growth of leaves hangs from the branchlet like a long beard, from which the tree receives, in some localities, the name "Pino barba caida." In the herbarium the long leaves, deciduous sheaths, and the decurrent bases of the bracts, present a combination of characters not found in other species. Plate XVI. Fig. 155, Cone. Fig. 156, Cone. Fig. 157, Leaf-fascicle. Fig. 158, Magnified leaf-section. Fig. 159, Tree at Ferraria de Tula. [Illustration: PLATE XVI. P. LEIOPHYLLA (151-154), LUMHOLTZII (155-159)] =VIII. LONGIFOLIAE= Seed-wing adnate to the nut. Leaves long, in fascicles of 3, the sheath persistent. Apophysis of the cone prolonged and reflexed 22. longifolia. Apophysis of the cone low-pyramidal 23. canariensis. 22. PINUS LONGIFOLIA 1803 P. longifolia Roxburgh ex Lambert, Gen. Pin. i. 29, t. 21. 1897 P. Roxburghii Sargent, Silva N. Am. xi. 9. Spring-shoots uninodal. Leaves in fascicles of 3, the sheath persistent, from 20 to 30 cm. long; resin-ducts external, the hypoderm often in large masses, some or all of the endoderm cells with thick outer walls. Cones from 10 to 17 cm. long, short-pedunculate, ovoid-conic; apophyses lustrous brown-ochre or fuscous brown, elevated into thick, often reflexed, beaks with obtuse mutic umbos; seeds with large nuts and adnate striated dark gray or fuscous brown wings.