On the validity of some fossil species of Liriodendron. 
THEO. HOLM. 
WITH PLATE XXIII. 
The making of species of fossil plants has been increasing 
rapidly during the last few years, and many new species have 
been recorded from this country. It seems, however, when 
we study the various articles that have been published upon 
the subject, as though there were a rivalry to see who could 
establish the largest possible number of species. Whether or 
not this is true, American paleobotanists are certainly going 
too far in giving incomplete and insignificant leaf-fragments 
specific names. Any botanist who studies our existing flora 
can not avoid observing the great variation that exists in the 
foliage of our trees and herbs; and must admit that it would 
be very difficult to refer all these leaf-forms to their respective 
Species if they had been detached from their branches. 
Another fact that makes the study of paleobotany still more 
difficult is the usual absence of flowers and fruits. The 
identification of even the most completely preserved leaf must, 
therefore, be more or less uncertain, and when we consider 
fragments of such leaves, which do not show anything but a 
from the excellent illustrations by Sachs}, Wiesner’, and 
Stahl. 
But it would really seem as if our paleobotanists ignore 
these facts, and consider their fossil leaves only as dead matter 
Prasadadas died 8 ie 
1Sachs, Julius: Die Anisotropie der Pflanzenorgane. Vorlesungen fiber 
Pflanzen-Physiologie 855. 1882, 
* Wiesner, Jul.: Untersuchungen tiber den Einfluss der Lage auf die Gestalt 
Pflanzenorgane. Sitzungsber. d. kais. Akad. d. Wiss., math.-naturw. Classe 
*Stahl, E.: Regenfall und Blattgestalt, em Beitrag zur Pflanzenbiologie- 
Ann. du Jardin Botan. de Waluuuee 11: 98-182. 1893. 
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