14 



THE PINES OK MEXICO. 



PlNUS L.EIOPHYLL.A VAR. CHIHUAHUANA M VAR. 



Pinus chihuahuana Engelmann, Wislizenus Tour Nor. Mex. 103 {Senate Doc, 1848). 

 Parlatore, DC. Prodr. xvi, pt. 2, 397 (1868). Hemsley Bot. Biol. Cent. Am. iii, 186 (1883). 

 Toumey, Gard. & For. viii, 22, fig. 3 (,1895). Sargent, Silva N. Am. xi, 85, t. 566 (1897); 

 Man. Trees N. Am. 14, fig. 13 (1905). Britton, N. Am. Trees, 18, fig. 12 (1908). 



Differing from the species by its stouter leaves usually in fascicles of 3 and 4, the leaves of 

 the type being almost invariably in fascicles of 5. 



Growing beyond the northern boundary of Mexico, in southern Arizona and New Mexico, 

 and extending southward along the north western Sierras to the Territory of Tepic and the 

 State of Zacatecas, where it merges into the typical form. 



Nelson, 4558 (398620) El Salto, Durango ; 6013 (398624) Sierra Madre, Chihuahua. Rose, 3587 (302564) 

 3588 (302565) Mesquitec, Jalisco; 2123 (301027) Santa Teresa, Tepic; 2377 (301289), 2378 (302735) Sierra 

 Madre, Zacatecas; 2405 (301315) San Juan Capistrano, Zacatecas; 2742 (301671-2) Plateado, Zacatecas. 

 Palmer, 83, 775, Durango. Shaw, Sandia, Durango. 



The species and the variety are alike except for the stouter and fewer leaves of the latter. Both sprout 

 freely along the trunk. When a tree is felled the stump in a few years becomes completely concealed by the 

 numerous shoots that grow from it. 



Some cones of this species resemble in size and general appearance those of P. teocote var. macrocarpa, but 

 the triennial cone and and early deciduous fascicle sheaths of P. leiophylla form a combination of characters not 

 found in any other known species of Pine. Triennial cones occur in two species of Pinus only, P. leiophylla and 

 the Mediterranean P. Pinea L. 



PLATE VII. 



Fig. 1 

 2 



3 

 4 



5 



6 



Leaves of the species. 



Leaf-section, magn. 30 diam. 



Cone. 



Branch showing triennial fructification. 



Cone-scale of first year, magnified. 



Cone-scale of second year, magnified. 



Fig. 7. 

 " 8. 



" 9- 



" 10. 



" 11. 



Cone-scale of third year, magnified. 



Cone. 



Trunk of tree with sprouts. 



Leaves of oar. chihuahuana. 



Leaf-section of same, magn. 30 diam. 



