47. echinata

37. PINUS PSEUDOSTROBUS

1839 P. pseudostrobus Lindley in Bot. Reg. xxv. Misc. 63.
1839 P. apulcensis Lindley in Bot. Reg. xxv. Misc. 63.
1842 P. tenuifolia Bentham, Pl. Hartw. 92.
1846 P. orizabae Gordon in Jour. Hort. Soc. Lond. i. 237, f.

Spring-shoots uninodal, conspicuously pruinose. Bark-formation late, the
cortex of young trees smooth. Leaves in fascicles of 5, sometimes of 6,
from 15 to 30 cm. long, drooping; resin-ducts medial, hypoderm variable
in amount, often in very large masses, the outer walls of the endoderm
thick. Conelets mucronate. Cones from 7 to 14 cm. long, ovate or
ovate-conic, symmetrical or oblique, deciduous and often leaving a few
basal scales on the trees; apophyses rufous or fulvous brown, flat,
elevated or, in one variety, prolonged in various degrees, the
prolongations nearly uniform or much more prominent on the posterior
face of the cone, the mucro usually deciduous.

A species of the subtropical and warm-temperate altitudes of Mexico
and Central America. Its range includes both eastern and western
slopes of the northern plateau. Its northern limit is in Nuevo Leon,
and it probably reaches in Nicaragua the southern limit of pines in
the Western Hemisphere. It is distinguished from all its associates by
the smooth gray trunk of the young trees, by their long internodes,
and by their drooping gray-green foliage.

Some cones of this species develop protuberances of all degrees of
prominence up to the curious cone collected in Oaxaca by Nelson (var.
apulcensis, Shaw, Pines Mex. t. 12, fig. 8). There is also a
remarkable difference in the amount of leaf-hypoderm. On many trees of
the western part of the range this tissue forms septa across the green
mesophyll. Such partitions are sometimes met in other species, P.
Pringlei or P. canariensis, where the hypoderm is abundant. But in P.
pseudostrobus they appear in some leaves of weak, as well as of strong
hypoderm (var. tenuifolia, Shaw, Pines Mex. t. 13, ff. 2, 4, 5, 7, 8).

Plate XXIV.

Fig. 211, Cone. Fig. 212, Two cones of var. tenuifolia. Figs. 213,
214, Two cones of var. apulcensis. Fig. 215, Magnified section of 3
leaves of var. tenuifolia. Fig. 216, Magnified section of 2 leaves
of the species. Fig. 217, Bud destined to produce staminate flowers.
Fig. 218, Ten-year old branch showing smooth cortex. Fig. 219, Young
and