47 
poplar are rhomboid-ovate, cuneate at the base, and not whitened 
beneath, I do believe that, if not distinct from both, it is a variety 
of P. balsamifera rather than of P. angustifolia. The leaves are 
rhomboid, on petioles 1-2 inches long (in P. angustifolia they are 
only ¥%-1 inch.), generally long-acuminate, shining on both sides, 
regularly crenate except at the cuneate base. The teeth are larger, 
more distant, and more regular than in P. angustifoha. Dr. Bessey 
states that the general appearance of the true P. angustifolia is 
more that of a willow than of a poplar, which is not at all the 
case with this. The general growth, the size, form, and color of 
the trunk were somewhat between those of P. dalsamifera and P. 
angulata, although most like the former. The long and slender 
petioles remind one of the latter or even of the Quaking Aspen. Dr. 
S. Watson says in his Revision about P. angustifolia : “Two forms are 
spoken of, the Yellow Cottonwood, making fair lumber, and the 
Black Cottonwood, common and extensively planted in Utah, but 
the wood is considered worthless.” May be, this is the former. I saw 
it growing only at one place, viz., in Carter Canon, where it grew 
along the brook, together with P. angulata. The grove contained 
Over 109 trees of this poplar, 40 to 60 feet high, some measuring 
18 inches in diameter. Carter Canon, S. B. Co., Juiy 26.” 
The above is an abstract from my list of plants, collected in 
Western Nebraska, in the summer 1891, for the U. S. Department 
of Agriculture. John M. Holzinger, Assistant Botanist of the 
Same department, who afterwards examined my collection, wrote 
me, among other things concerning this tree: “I make it, after care- 
ful consideration, Populus angustifolia, James. The difficulty seems 
to arise from the mature leaves: herb. material generally has 
them undeveloped.” I still believe, however, the above to be dis- 
tinct from P. angustifolia, James, or, at least, from what we have 
been used to call so. I saw both, this summer:—my No. 
372 both with undeveloped and mature leaves, and the true P. 
angustifolia, on the 28th of June, at which time the leaves, although 
not mature, yet had received their form. Specimens with mature 
leaves are found in the herbarium of the University of Nebraska. 
J udging from the material on hand, I do not hesitate to declare 
them to be distinct species. Perhaps, if I had a fuller series of 
Specimens, I would be of another opinion. Taking for granted 
