te. 
54 : BOTANICAL GAZETTE [JULY 
south of the southern limits of Chicago. The difficulty experienced 
in bringing this type of oak under any described species early led toa 
suspicion of hybridity, and further observations have confirmed this 
view. ‘The fact that oaks hybridize somewhat readily is strongly in 
favor of such a solution, when one or two isolated trees are found in the 
midst of well-marked species of the ordinary kinds. I find no record 
of a cross between Quercus palustris Du Roi and Q. coccinea Wang, 
which evidently takes places here. Dr. Engelmann‘ reported a hybrid 
of Q. palustris and Q. imbricaria found near St. Louis about 1870, an 
account of which was also given by Alexander Braun.? This appears 
to be the only case hitherto noted of any hybrid of Q. palustris. It is 
so much more nearly allied in the character of its leaves to Q. coccinea 
than to Q. imbricaria as to add to the difficulty of distinguishing 4 
cross between the two if the leaves only are taken into account, and 
reliance must therefore be placed principally upon other distinctions, 
though the color of the autumn leaves is a clear gain. ‘This is the 
only section near Chicago where I find Q. palustris, and it appears to 
reach its northern limit near the southern end of Lake Michigan here, 
extending eastward into Indiana and southward in Cook and Will 
counties, Ill., along Thorn creek and it branches. Q. coccinea is more 
abundant than usual in the woods where the hybrid is found and more 
sharply defined from Q. velutina than customary here. Although there 
aré some features that might be better defined by an assumption of @ — 
cross of Q. palustris with the latter, the acorns and the autumn leaves 
are much better explained by a cross with the former. In habit and ; 
appearance of the trunk the hybrid is so nearly like Q. palustris as at 
first to have been taken for it. It is a tree of recent growth, qm in 
diameter and about 13" high. The characters are as follows : : 
Top oblong, the limbs spreading, the lower drooping. Bark of 
trunk dark gray-brown, tinged with green, close and rather smooth, 
palustris. Young shoots pubescent, becoming smooth or nearly so ie 
autumn. Branches of the first year brown, tinged with yellow, bie 
small, scattered, slightly raised lenticels. Older branches gray, tinged 
with red. Winter buds ovate-conical, obtusish, slightly angled, oF 
long, pubescent with pale or white hairs. Bud scales oval, obtuse 
* Botanical Works 405. 
* Bot. Zeit. 29 : 202, 1871, 
