Seed with a long effective wing adnate to the nut.
The base of the seed-wing corresponds to the marginal spermoderm of the Flexiles but is prolonged into an effective adnate wing. This form of wing appears again in the species Balfouriana and in the group Longifoliae.
| Cones very long, usually exceeding 25 cm. | |
| Cone-scales prolonged and reflexed | 6. ayacahuite. |
| Cone-scales appressed | 7. Lambertiana. |
| Cones less than 25 cm. long. | |
| Cone-scales prominently convex. | |
| Leaves less than 7 cm. long | 8. parviflora. |
| Leaves 9-12 cm. long | 9. peuce. |
| Leaves 12-18 cm. long | 10. excelsa. |
| Cone-scales thin, conforming to the surface of the cone. | |
| Cone relatively longer, its phyllotaxis 8/21 | 11. monticola. |
| Cone relatively shorter, its phyllotaxis 5/13 | 12. strobus. |
6. PINUS AYACAHUITE
- 1838 P. ayacahuite Ehrenberg in Linnaea, xii. 492.
- 1848 P. strobiformis Engelmann in Wislizenus, Tour Mex. 102.
- 1857 P. Veitchii Roezl, Cat. Graines Conif. Mex. 32.
- 1858 P. Bonapartea Roezl in Gard. Chron. 358.
- 1858 P. Loudoniana Gordon, Pinet. 230.
Spring-shoots glabrous or pubescent. Leaves from 10 to 20 cm. long, serrulate, their stomata ventral only, their resin-ducts external, often numerous. Cones from 25 to 45 cm. long, pendent on long stalks, subcylindrical or tapering, often curved; apophyses pale nut-brown, dull or sublustrous, varying much in thickness, prolonged in various degrees, the prolongations patulous, reflexed, recurved or revolute; seeds of the southern typical form with a long wing, the wing diminishing and the nut increasing in relative size northward.
The White Pine of Mexico and Guatemala grows on mountain-slopes and at the head of ravines. It is not very hardy in cultivation except in the milder parts of Great Britain and in northern Italy, where the forms of central and northern Mexico have been very successful. The species is best recognized by the prolonged apophyses of its large cone.
The variations in the size of the cone and in the prolongations of its scales are many, but of far more significance is the remarkable variation of the seed-wing, which is long in the southern part of the range, short and broad in central Mexico, and rudimentary, like the seed of P. flexilis, in the north. This makes it possible to establish two well defined varieties—Veitchii and brachyptera. The three forms of the species present a gradation from the long effective wing of the Strobi to the rudimentary form of the Flexiles. Many of the seed-wings of the var. Veitchii correspond, in their short broad form and opaque coloring, with the characteristic wing of P. Lambertiana.
[Plate X]. (leaves and cones much reduced).
Fig. 103, Cone and cone-scale of var. Veitchii. Fig. 104, Cone and seed of var. brachyptera. Fig. 105, Cone-scale of the typical form. Figs. 106, 107, Leaf-fascicles and magnified leaf-sections.