64 GENUS PINUS 



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. 1. 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. 



38. PINUS MONTEZUMAE 



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



1832 P. MoNTEZtJMAE 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. SiNCLAiHii 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 becom- 

 ing 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 prickle 

 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; apophy- 

 ses dull, rarely lustrous, nut-brown, or of various shades of fuscous brown to nearly black, flat, tumid, 

 pyramidal or sometimes slightly protuberant, the prickle 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 altitudes 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 sturdy Pine and its numberless variations present the most remarkable example of adapta- 

 tion in the genus. The variations are mostly those associated with changes of environment 

 dimensions of cone and leaf and the number of leaves in the fascicle. These are so accurately corre- 

 lated with altitude 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 altitudes 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. 



