DIPLOXYLON
Bases of the bracts subtending leaf-fascicles decurrent. Leaves serrulate; fibro-vascular bundle double; stomata dorsal and ventral. Cones with a dorsal umbo, the phyllotaxis complex. Wood hard, with dark resinous bands, the annual rings clearly defined.
In this section there are a few species combining the essential characters of Diploxylon with important characters of Haploxylon. A subsection, Parapinaster, is established for these exceptional species.
| c. Parapinaster | Species with the fascicle-sheath or seed-wing of Haploxylon. |
| d. Pinaster | Sheath persistent, seed-wing articulate, effective. |
Parapinaster
| Sheath of the leaf-fascicle deciduous | VII. Leiophyllae. |
| Sheath of the leaf-fascicle persistent. | |
| Seed-wing of the Strobi | VIII. Longifoliae. |
| Seed-wing of the Gerardianae | IX. Pineae. |
VII. LEIOPHYLLAE
| Sheath of the leaf-fascicles deciduous. | |
| Leaves short, erect, the fructification triennial | 20. leiophylla. |
| Leaves long, pendent, the fructification biennial | 21. Lumholtzii. |
20. PINUS LEIOPHYLLA
- 1831 P. leiophylla Schlechtendal and Chamisso in Linnaea, vi. 354.
- 1848 P. chihuahuana Engelmann in Wislizenus, Tour. Mex. 103.