CATALOGUE. 261 
so difficult as Pinus, but I find it impossible to unite it with any other of 
the allied species. It has the cone of P. ponderosa, especially of that form 
figured by Torrey as P. deflexa, and, like all forms of that species, it has 
the peculiarity that the fallen cones, found on the ground, are always 
imperfect, their lowest part remaining attached to the branch for another 
season; I do not know of any other pine with this singular character. 
But we could not well class this 5-leaved pine with the 3-leaved ponderosa. 
On the other hand, the form of the cone and its scales will not permit us to 
refer it to the Mexican P. Montezuma, though the structure of the leaf is 
very similar to that of this polymorphous species, which appears to include 
even P. Hartwegii. The three parenchymatous ducts of the leaf and the 
strengthening cells* within the sheath of the vessels are exactly as we find 
them in Montezuma, and different from ponderosa. 
Pinus ponperosa, Dougl. Parlat. /. c. 305.—A large tree, with large and 
spreading head, thick, deeply cracked, red-brown bark, and heavy, resinous, 
yellowish wood; thick branchlets, rough from leaf-scars and the persistent 
remnants of bracts; leaves in twos or mostly in threes, 4-8’, in some rare 
forms 10-12’, long, ?’ wide, with sheaths at first 1’ long, when old with- 
ering to 2 or 3” long; staminate flowers cylindric, with an involucre of 10 
or 12 scales, the lowest pair of which is about two-thirds as long as the 
innermost; anthers with a large sub-orbicular crest; fertile aments sub- 
terminal; patulous cones oval or rarely elongated, very variable in size, 
2-6’ long; knob of the scales more or less prominent, and in some forms 
even recurved, bearing a rather stout prickle; seeds black, ridged on the 
lower side, wing broadest in the middle; cotyledons 6-8, or in the largest 
seeds as many as 10. 
Colorado, New Mexico, and Arizona, extending through the Northern 
Rocky Mountains and adjacent regions to Oregon and California, mostly in 
the middle altitudes; the most common and most useful timber of many 
*This name has been given to longitudinal cells with very thick walls, destitute of chlorophyll, 
which are characteristic of most pine-leaves, and by their different disposition aid in distinguishing them 
from one another. They are generally arranged close to the epidermis, and especially in the angles of 
the leaves, and have usnally about the same diameter as the epidermis-cells themselves. We find them 
also occasionally surrounding the ducts, e.g.in P. ponderosa, also in the Cembroid Pines and in P. Bal- 
fouriana and P. aristata; while in P. flexilis they always leave the ducts free, a character by which 
wo can readily distinguish the leaves of these species, otherwise so similar. Not rarely are they found 
within the sheath, strengthening, as it seems, the centre of the leaf. 
