1876.] Botany. 235 
(1.) The pith of the poison ivy, wherever the vine is of moderate size, 
and is found adhering closely either to the bark of a living tree or to any 
soft, decaying substance, is located from three to ten times nearer the 
outer than the inner side of the stem, and sometimes still more eccen- 
trically ; the annual layers of wood as well as the bark becoming corre- 
spondingly thickened on the side next the support. 
(2.) This eccentricity diminishes and frequently disappears altogether 
at points where there is no attachment by the rootlets. 
(3.) It is greatly reduced in vines which cling to hard substances 
which the rootlets are unable to penetrate, as a stone wall or a dry post. 
That all these facts are in harmony with the theory of the absorption 
of nourishment from the support, in so far as any form of parasitism is 
implied, cannot of course be maintained. The last élass of observations 
described may be regarded as directly negativing such an assumption. 
Besides, I have seen nothing to render it probable that the rootlets ever 
pierce the outer bark. But, on the other hand, these facts do all unite 
in pointing to a physical connection of some kind between the penetra- 
tion of the rootlets and the eccentricity of the pith. The notion thus far 
entertained, and which has found its way into our standard text-books, 
that these rootlets are “ not for absorbing nourishment, ‘put for climb- 
ing,”* may in future require some modification. Yet, admitting this 
physical connection, there remain puzzling physiological questions. If 
these rootlets perform the function of true roots, and find congenial soil 
In the corky layer of bark, in the soft mass of decomposed wood, and 
even to some extent in the minute cryptogamic vegetation that always 
exists among them even when clinging to walls of brick or stone, how 
does this explain the singular behavior of the pith and the strange 
eccentricity of the annual rings ? — Lester F. Warp 
Sers of Dr. Edward Palmer’s recent collection of plants of San Diego 
Co., California, and of the Tantillas Mountains in Lower California, near 
the boundary, will shortly be ready for distribution. They will probably 
number about three hundred species, and will be sold at ten dollars per 
hundred. Address Sereno Watson, Cambridge, Mass. 
Rosinta nisripa.— Can an of our readers procure specimens of 
the fruit of this plant for Professor Gray, of Harvard University, Cam- 
bridge? The pods are almost unknown. 
BOTANICAL PAPERS in Recent PERIODICALS. — The Journal of Bot- 
_ “ny (Trimen), February. S. Kurz, On the Species of Glycosmis (plants 
of the orange tribe). A. E. Eaton, Plants of Spitzbergen. H. F. Hance, 
New Orchids from Hong Kong. Reichenbach fils, Descriptions of three 
ts. W. B. Helmsley, Notes on the Flora of Sussex. R. A. Prior, 
On Rumex hydrolapathum and R. maximus. G. Dickie, On Marine 
Alge from Kerguelen Island. M. J. Berkeley, On a New Agaricus 
from Kerguelen Island. Dr. Gray’s paper on Æstivation and its Termi- 
nology is reprinted in this number. a" 
1 Gray’s Lessons, page 34. 
