found, and specimens that I have collected in Sandia, Durango (issued
by Pringle, through a misunderstanding, under the name P. Roseana,
ined.) show such fascicles on the fertile branches.

Plate XXVI.

Fig. 230, Cone and seed of var. Jeffreyi. Fig. 231, Cone of var.
macrophylla. Fig. 232, Cone of var. scopulorum. Fig. 233, Magnified
leaf-section and cells of leaf-endoderm. Fig. 234, Magnified dermal
tissues of the leaf, showing uniform and multiform hypoderm.

[Illustration: PLATE XXVI. PINUS PONDEROSA]

40. PINUS TEOCOTE

1830 P. teocote Schlechtendal & Chamisso in Linnaea, v. 76.

Spring-shoots uninodal, or sometimes multinodal. Leaves prevalently in
fascicles of 3, but varying from 3 to 5, from 10 to 20 cm. long;
resin-ducts medial, sometimes with an internal duct, hypoderm biform,
endoderm with thick outer walls. Conelets mucronate. Cones usually very
small, from 4 to 6 cm. long, but with a larger varietal form, ovate to
long-conic, symmetrical; apophyses nut-brown, flat or tumid, the mucro
usually deciduous.

This species grows at temperate altitudes from Chiapas to Nuevo Leon,
associated with temperate Mexican species such as P. patula, P.
leiophylla and others, and is easily recognized by its small cone. The
variety with a larger cone (var. macrocarpa, Shaw, Pines Mex. t. 10) I
have found growing in mixed groves of P. teocote and P. leiophylla. It
resembles the latter in cone and leaf, but lacks the peculiar
character that distinguishes P. leiophylla from all other Mexican
species--the triennial cone. Some of the specimens of Hartweg No. 441
belong here, as well as Pringle's specimens, Nos. 10013, 10018,
distributed as P. eslavae, ined.

Plate XXVII.

Fig. 235, Two cones of the species and the larger cone of the
variety. Fig. 236, Leaf-fascicle and magnified sections of two
leaves. Fig. 237 a, Dermal tissues of the leaf magnified; b,
magnified cells of the leaf-endoderm. Fig. 238, Habit of the tree.

41. PINUS LAWSONII

1862 P. Lawsonii Roezl ex Gordon, Pinet. Suppl. 64.
1905 P. Altamirani Shaw in Sargent, Trees & Shrubs, i. 209, t. 99.

Spring-shoots conspicuously pruinose, uninodal or not infrequently
multinodal. Leaves in fascicles of 3, 4 or 5, not exceeding 24 cm. in
length; resin-ducts internal, often with one or two medial ducts,
hypoderm biform, endoderm usually with thin outer walls. Conelets
mucronate. Cone