114 ILLINOIS ACADEMY OF SCIENCE 



Cup dilated saucer-shaped, abruptly constrkted 

 about the acorn. f. coronata Vasey. 



Leaves obovate-oblong, irregularly lobed or incised. 



f. hctcrophyUa Trel. 



So far as I know, each of the fruit forms (pi. 142) may be 

 expected wherever the species occurs, though the depressa 

 and coronata forms are less frequent than those with the 

 more typical elongated acorns or narrow cups. The 

 heterophyllous aberrant, comparable with forms offered by 

 many other species of oak, has been collected at Spooner 

 Lake, Wisconsin, (Miss Ruth Marshall), and in Clayton 

 County, Iowa (Pammel). 



The synthetic characters of Quercus eUipsoidalis have 

 led to the supposition that one or more of the forms or 

 individuals that are here called by this name may be 

 really of Iwbrid origin between Quercus j^dlnstris, Q. coc- 

 cinca, Q. velutina, — which is meant sometimes when the 

 name Q. coccinea is used in the former broad sense, and 

 possibly Q. maxima. The tree which Mr. Hill considered 

 to be a hybrid of palustris and coccinea before he dis- 

 tinguished his own species, as is noted on one of the sheets 

 representing it was considered subsequently to be rather a 

 cross between palustris and ellipsoidalis itself; but I 

 should say that it is merely a form of the latter. Though 

 of restricted range, for an oak, this species is too abun- 

 dant in its region, and too distinct from its congeners, to be 

 considered as of a different nature from these notwith- 

 standing a greater variety in fruit and buds than any of 

 them shows except Q. velutina. On the other hand, there 

 is no reason to suppose that it may not cross with one or 

 more of these species, and as it becomes better known in 

 individual trees such hybrids are very likely to be discov- 

 ered. 



Specimens that suggest such an origin are one from Kil- 

 bourn, Wisconsin, collected by Miss Marshall in August, 

 1916, which in leaf and fruit is scarcely more than the less- 

 lobed form of velutina though as yet with relatively small 

 buds for the black oak ; and an eight-foot bushy tree in the 

 sands of Chicago which Dr. Pepoon collected in September, 

 1916. Though the acorns of this are more persistently 

 downy than is usual in ellipsoidalis and its buds are un- 



