The wood of this subsection differs from that of other species, except that of P. pinea, in the Picea-like characters of the medullary rays—tracheids with smooth walls combined with the thick walls and small pits of the ray-cells. On the character of the seeds the species may be divided into three groups.
| Seeds wingless | IV. Cembroides. |
| Seeds with a short, ineffective, articulate wing | V. Gerardianae. |
| Seeds with a long and effective wing | VI. Balfourianae. |
IV. CEMBROIDES
Seeds wingless, the nut large, wholly or partly bare of membranous cover. Cones varying from yellow-ochre to deep red-orange in color.
These are the Nut Pines, growing on the arid slopes and table-lands above the great plateau of northern Mexico and its extension into the southwestern United States. There are three distinct species.
| Leaves entire, the sheath deciduous. | |
| Cones subglobose, subsessile | 13. cembroides. |
| Cones cylindrical, pedunculate | 14. Pinceana. |
| Leaves serrulate, the sheath persistent | 15. Nelsonii. |
13. PINUS CEMBROIDES
- 1832 P. cembroides Zuccarini in Abh. Akad. Münch. i. 392.
- 1838 P. Llaveana Schiede in Linnaea, xii. 488.
- 1845 P. monophylla Torrey in Frémont's Rep. 319, t. 4.
- 1847 P. Fremontiana Endlicher, Syn. Conif. 183.
- 1848 P. edulis Engelmann in Wislizenus, Tour. Mex. 88.
- 1848 P. osteosperma Engelmann in Wislizenus, Tour. Mex. 89.
- 1862 P. Parryana Engelmann in Am. Jour. Sci. ser. 2, xxxiv. 332 (not Gordon).
- 1897 P. quadrifolia Sudworth, Bull. 14, U. S. Dep. Agric. 17.
- 1903 Caryopitys edulus Small, Fl. Southeast. U. S. 29.
Spring-shoots pruinose. Leaves from 2 to 6 cm. long, in fascicles of 1 to 5, the sheath-scales revolute at the apex, then deciduous; stomata ventral, or ventral and dorsal; resin-ducts external. Scales of the conelet armed with a minute prickle. Cones from 4 to 6 cm. long, subglobose, subsessile; apophyses lustrous ochre-yellow, crowned with a quadrilateral umbo bearing the minute prickle of the conelet; seed flaxen yellow when fresh, its testa bare, the spermoderm adnate to the cone-scale.