+ 
802 The American Naturalist. [September, 
the possession of a very remarkable appendage at the base of the | 
blade. This appendage seems to constitute a miniature reflex of | 
the leaf itself, projected backward over the petiole as a lobate 
expansion. It is palmately nerved like the principal blade, the | 
primary nerves entering the lobes. These sometimes differ in ; 
number from those of the leaf, amounting to six in two of my 
specimens. They also vary considerably in length and shape. 
[See Figs. 2-5 of the paper last cited.] 
“This basilar appendage is extremely interesting. It is not 
stipular, since it arises from the summit of a petiole of consid- 
erable length, six centimetres of it being preserved in one speci- 
men without showing the attachment. Neither is it bracteal, and 
there seems no way but to regard it as a veritable part of the 
main blade, to which it is joined by a broad neck of parenchy- 
matous tissue. 
* There is good reason to regard this character as an argument 
in favor of referring these leaves to Platanus rather than to Aralia 
or any other genus. The leaves of Platanus have a tendency to 
produce appendages of various kinds. A good illustration of 
this is seen in the interesting P. appendiculata Lx., from the 
auriferous gravels of the Sierra Nevadas [Fig. 8 of that paper], 
where the generic affinities are not at all in doubt. But here the 
appendages appear to be stipular, though large and quite near 
to the base of the limb. In the sycamore of this country the 
stipules are prominent, and often lobed and nerved much like 
these appendages. They also often appear at the base of young 
branches bearing several leaves which are likewise provided with 
true stipules of the same form. In addition to this, however, 
there sometimes occurs a true basilar lobe or wing-like expansion - 
on the leaf itself, which in the more marked examples very - 
closely resembles those of the fossil impressions described. [Fig- E 
2 of the present paper represents such a case, and also shows ^ 
the stipules as they are often produced.] Long before I had seen 
the fossil leaves I had remarked this tendency in P. occidentalis 
to develop such. basilar appendages, and I had collected and pre 
served specimens of the leaves that bore them to illustrate this 
peculiarity. : 
