38 
BOTANY. 
the scales hearing small acute recurved spines. The cones grow singly or in clusters of from 
two to four, generally at the extremities of the smaller branches, and are not pendent, as in the 
group of pirn s to which P. Lambertiana and P. sirobus belong. The seeds are somewhat 
larger than apple seeds, and form the principal subsistence of several kinds of birds. 
The average length of the cones of P. ponderosa is perhaps four inches, though in the same 
grove of trees I have seen all the variations I have mentioned. On the flanks of Lassen’s butte 
we found a pine prevailing over an area of several square miles, differing in nothing, as I could 
perceive, from the common P. ponderosa , except that the cones were all double the average size; 
I could not doubt, however, that it was a mere variety of the common species. 
The hark of P. ponderosa affords one of its most noticeable and distinctive characters. It is 
light yellowish brown, (cork color,) and is divided into large plates, four, six, or eight inches 
in breadth, which are flat and smooth, and enable one to distinguish the trunk of this tree at a 
considerable distance. These plates of cork-like bark are made the repositories of acorns by 
the woodpeckers, and it is a very common thing to see large numbers of these trees having the 
hark of the trunk cut into a honeycomb by thickly set holes as large as thimbles, or as thickly 
studded with inserted acorns. 
The wood of the yellow pine is generally highly resinous, and, though heavy, is brittle and 
less valuable than that of the sugar pine. Like the “ pitch pine” of the eastern States, it is, 
however, sometimes of excellent quality, containing little resin, soft and tough. The yellow 
pine exhibits a tendency to twist, which is very noticeable in a forest of these trees, the grain of 
trunk and branches being often seen coiled into the closest possible spiral. 
This is undoubtedly the tree described by my friend Dr. Engelmann under the name of P. 
brachyptera , the specimens on which his description was based having the wings of the seeds 
unusually shortened. In the normal form the seed-wings are not shorter than in other pines 
having cones of equal size. 
Although I have taken Douglas’ name, which was the first applied to this tree in the far west, 
I have been inclined to doubt whether it should not be considered a mere variety of P. rigida. 
I have not been able to find any constant differences between the fruit or foliage of the two 
species. The western tree is, however, much more robust, growing taller and larger, the bark 
smoother, and the wood generally less resinous. 
The same differences are also noticeable between Abies Canadensis of the west and east, and 
may very well depend on a soil and climate which is particularly favorable to the growth of 
coniferous trees. 
The various phases exhibited by P. rigida, going from New England to Georgia, show the 
influence of soil and climate in modifying its habit. It should also be observed that its range 
is very great in the eastern States, and that it extends from Louisiana westward nearly to New 
Mexico, where P. ponderosa occurs—a fact which strengthens the probability that they are 
identical, and that, as a single species, this tree bridges over the continent south of the central 
desert, in the same way that Abies Canadensis stretches across from Lake Superior to Oregon, 
north of that area. 
I have before me, as I write, specimens of the cones and foliage of P. ponderosa from the 
immediate vicinity, and perhaps from the very trees, where Douglas obtained the cone and 
leaves which he sent to Europe ; and on the Columbia I observed the tree where I know he had 
botanized. There is, therefore, no possibility of being in error as to the tree which he designated 
by the name of P. ponderosa. The cone sent home by Douglas was immature and deformed, 
