THE PINES OF MEXICO- 



27 



PlNUS OOCARPA VAK. MICROPHYLLA. N. VAR. 



Leaves much shorter and more slender than those of the species, 8-13 cm. long. 

 Sinaloa and the Territory of Tepic. 



Rose, 1755 (300624-5) Colomas, Sinaloa; 1997 (300890) Pedro Pau'o to San Rlasato, Tepic. Palmer, 1998, 

 Tepic. 



The specimens of this variety that have been collected indicate a limited range on either side of the boundary 

 between Sinaloa and Tepic. The cones are distinctly of the oocarpa form, although with thin scales and slender 

 peduncles, but the leaves are very much shorter and thinner than those of the species and, were it not for the 

 cones, would scarcely be recognized as belonging even to a variety of P. oocarpa. 



Pinus oocarpa can easily be recognized by its characteristic cone and by the peculiar section of its leaf. When 

 one of these characters fails the other is usually present. The leaf-section, however, is not invariable and it 

 is advisable, in investigating this or related species, to examine a number of leaves. The cone, too, does 

 not always conform to the type. There are ovate or long-conical shapes which do not suggest the species. 

 A form from Guatemala (Plate XX, fig. 12) collected by Kellermann, was also found by Nelson (No. 

 3681). This, according to Nelson, was a single tree in a grove of P. oocarpa at Huehuetenango, Guatemala. This 

 form, if it proves to be common, may deserve a varietal name. 



The thickening of the basal portion of the seed-wing is more conspicuous in this species than in others of this 

 section. The base above the nut is thick and rigid, the upper portion of the wing is membranous, the 

 two parts meet in an oblique line, along which the membranous part is easily broken away. Apparently the re- 

 inforced base contributes something toward the security of the grasp of the wing on the nut, for, while collecting 

 Pine-seeds in Mexico, it was found that the seed-wings of P. oocarpa and P. Pringlei were more difficult to remove 

 than those of other species not provided with this peculiar kind of wing. This character is most conspicuous in 

 the group of three California Pines with very large cones, P. Sabiniana Dong. P.Coulteri Don and P. Torreyana>~ 

 Parry. At Uruapan the fallen leaves of this and other long-leaved Pines are used in the manufacture of adobe, 

 the sun-dried brick of Spanish-American countries. 



PLATE XX. 



Fig. 1. Cone of Nelson 6845. Fig. 7. 



" 2. Cone of Rose 1755 (var. microphylla). " 8. 



" 3. ' Cone from Uruapan. " 9. 



" 4. Leaf -section of Nelson 2158, magn. 30 diam. " 10. 



" 5. Cone of Palmer 1998 {var. microphylla). " n. 



" 6. Leaf-section of Nelson 2406, magn. 30 diam. " 12. 



Cone from Uruapan. 



Leaves of Palmer 1998 (var. microphylla.). 

 Leaf-section of same, magn. 30 diam. 

 Leaves of Rose 1755 {var. microphylla). 

 Leaf-section of same, magn. 30 diam. 

 Cone of Kellermann 4521. 



