498 BROOKLYN BOTANIC GARDEN MEMOIRS 
existing Q. undulata, as he understood that species, in which were 
comprised entire, frequently toothed, and very deeply lobed forms, 
some of which he was disposed to segregate varietally as others have 
done specifically, but all intergrading, as he saw it, as forms of one 
single extremely polymorphic species (13). 
Similar polymorphism is shown by the many forms of associated 
European Tertiary oak leaves studied by von Ettingshausen and 
included in his conception of Q. palaeo-ilex. (Guided by venation 
studies, he was able to see in this species a foreshadowing of all of the 
modern types of oak foliage (14). In the absence of other knowledge 
than we now possess, I am disposed to think that in the holly-like form 
we may see a starting point for the successive reevolution of the various 
forms of leaf that Quercus has presented in the several geological ages, 
and now presents. 
REFERENCES 
1. An indispensable aid in locating first references to American 
post-carboniferous fossil plants, in this as in other genera, is Professor 
Knowlton’s catalogue of Cretaceous and Tertiary plants, published as 
Bulletin no. 152 of the United States Geological Survey—though it 
is now antiquated. 
2. Fruit of Q. consimilis and Q. paucidentata is figured by Hollick 
in Monograph 35 of the U. S. Geological Survey, Pl. 43. 
3. Nominal species of Quercus subsequently transferred to other 
families than Fagaceae are Q. anceps Lesq. (Diospyros ambigua), 
Q. Benzoin Lesq. (Persea Leconteana), Q. californica Lesq. (Mes pilo- 
daphne pseudoglauca), Q. chlorophylloides Knowlt. (Pisonia chloro- 
phylloides), Q. elkoana Lesq. (Carpinus grandis), Q. Lyellii Lesq. 
(Nectandra lancifolia), Q. microdentata Hollick (Dillenites microdenta- 
tus), Q. Mudgu Lesq. (Protophyllum Mudgit), Q. myrtifolia Lesq. 
(Sophora Lesquereuxit), Q. platania Lesq. (Platanus cordata), Q. 
retracta Lesq. (Myrica bentonensis), Q. Saffordi Lesq. (Banksia Saf- 
fordi), Q. semialata Lesq. (Anisophyllum semialatum). 
4. Nominal North American species of Quercus subsequently 
transferred to Dryophyllum are Q. crassinervis Lesq. (D. tennesseense), 
Q. gracilis Newb. (D. subfalcatum), Q. Moorii Lesq. (D. Moorit). 
5. The following European fossil species of Quercus are now believed 
to be represented by segregable American forms: Q. acrodon (Q. 
Lesquereuxiana Knowlt.), Q. angustiloba (Q. prae-angustiloba Knowlt.), 
Q. chlorophylla (Q. chlorophylloides Knowlt.), Q. furcinervis (Q. furci- 
nervis americana Knowlt.), Q. Johnstrupi (Q. raritanensis Berry), 
Q. Laharpi (Q. fraxinifolia Lesq.), Q. mediterranea (Q. peritula Cock.), 
Q. pyrifolia (Q. florissantensis Cock.), Q. voyana (Q. distincta Lesq.). 
