A HYBRID OAK. 
BY B. SHIMEK. 
The northern limit of the distribution of Quercus imdricaria Michx. and 
Quercus palustris Muench, in the valley of the Iowa river is reached near Hills 
in Johnson county. Here and southvrard both species occupy the alluvial bot- 
tom lands, and before the extensive clearing of the alluvial forests they were 
freely intermingled. In view of this fact and of the well-known tendency of 
oaks to hybridize it is not surprising that forms which are evidently hybrids 
occur. 
It is obviously difficult to determine the fact that hybridization has taken 
place in plants which require many years to reach maturity, when they first 
fully display their hybrid characters, and the only criterion which may be em- 
ployed is the mingling of recognized specific characters. Where species are very 
closely related this is manifestly difficult, if not impossible, but the task is much 
easier when the species are as well marked as the two here noted. 
Among the two or three probable hybrids which were found in a scattered 
clump of Q. imhricaria and Q. palustris on the alluvial bottom land south of 
Old Man’s creek, near Hills, the one here discussed shows this mingling of the 
characters of the parent species most clearly. 
A probable hybrid of these species has already been reported by Engelmann. 
Sargent says of it: “The leaves were broadly lanceolate, mostly acute at the 
apex, and entire or usually furnished with coarse triangular-toothed acute bristle- 
pointed teeth; they were pubescent at first, especially on the lower surface, but 
soon became glabrate, and lustrous above, paler below, from four to six inches 
long and from one to two inches wide. The fruit was mostly solitary and was 
borne on a stout peduncle sometimes half an inch in length; the nut was oblong, 
full and rounded at the apex, about as broad as it was long, light brown, and 
inclosed for about one-third of its length in the thin cup-shaped or turbinate cup 
covered by ovate scalqs rounded at the apex and clothed, except on the bright 
red-brown margins, with hoary pubescence.” 
It may be of interest to note that our hybrid agrees substantially with this 
description, but many of the leaves are quite deeply lobed, and these in some 
cases reach a width of more than three and one-half inches. 
Trans. St. Louis Academy of Sci., vol. Ill, p. 539, 1877. Also quoted in Sargent’s Silva 
of North America, vol. VIII, pp. 176-177, foot-note 9; 1895. 
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