38 BOTANY. 



the scales bearing 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 pines to which P. Lambertiana and P. strobus 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 bark 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 

 bark 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 &quot; pitch pine&quot; 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 corie 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, 



