NOTES ON THE LEAVES OF LIRIODENDRON. KV Theodor Holm, Assistant in the Department of Botany. (With Plates iv-ix.) Dnriug the spring of 1889, while engaged in studying the germina-tion of some of our native phmts, I collected quite a large number of germinating plantlets in the woods about Washington, especially along the Potomac shore. In the pursuit of these studies I found many speci-mens of our common Tulip-tree [Liriodendron Tulipifera), which, how-ever, did not particularly attract my attention, since their germination with the cotyledons above ground showed nothing especially remarka-ble; nevertheless I collected a number of them and brought them home for closer examination. I now observed, that although their germina-tion did not present anything of particular interest, they showed a pe-culiar fact in respect to their young foliage-leaves. The two or three leav^es developed upon these young plants showed a great similarity among themselves, and at the same time differed from those of the older or full-grown tree. 1 then began the examination of the foliage of the mature tree, and it was not long before I observed that there was a cer-tain regularity, depending upon the position of the different forms of leaves. It is a well known fact that there is a great variation in the leaves of our recent Liriodendron^ not only on the same tree, but even on the same branch, but as this circumstance does not seem to have been much discussed heretofore, it may be of interest, at least to paleobota-nists, to describe the Liriodendron leaf somewhat carefully. After having collected many fine specimens of the leaves, from very young trees and from the branches of some of the oldest ones in the vicinity of Washington, I began to examine the course of the v^ariation. First, however, I looked at the published descriptions of the tree, but it seems to be a fact so well known that the sj'stematic authors have not thought it necessary to mention it. I consulted Prof. Lester P. Ward about it, but he did not remember where these variations were descrit)ed by any author, but advised me to study certain paleobotaufcal publications, and called my attention especially to a paper by Dr. J. a. Newberry, Proceediugs National Museum, Vol. XIII— No. 794. 15
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