MAY 2 1 1913 
The Ohio T\Naturalist, 
PUBLISHED BY 
The Biological Club of the Ohio State University. 
Volume XIII. 
APRIL, 1913. 
No. 6. 
LMJRARl 
NEW YOR 
BOTANIC A 
garden 
TABLE OF CONTENTS. 
Schaffner—T be Classification of Plants, IX. 101 
McAvoy—L iliales of Ohio. 109 
Brain—A Preliminary List of the Acarina of Cedar Point. 131 
McLellan—M eeting of the Biological Club.. 132 
THE CLASSIFICATION OF PLANTS, IX.* 
John H. Schaffner. 
Our knowledge of the gymnosperms has been greatly advanced 
in recent years and it is now possible to discern the broad, general 
lines of relationship among them with some degree of certainty. 
Especially important have been the contributions on the morphol¬ 
ogy of the cycads and various conifers by Chamberlain and other 
Chicago botainists. 
In some orders, the phylogenetic relationships are still un¬ 
certain and much work remains to be done both on the cytology 
and on the histology of the stem. In certain genera even the 
gross organography is not completely known. Among the coni¬ 
fers, the Podocarpacese and certain Taxodiaceas greatly need 
serious attention. 
The recent discoveries in the Pteridospermae and other fossil 
groups and the finding of multiciliate, motile sperms in the living 
Cycadophyta have definitely related the Gymnosperms to the 
Ptenophyte phylum; and, although one would hardly look to any 
known living Gymnosperms as direct ancestors of the Angiosperms, 
yet it seems certain that the Angiosperms and the various groups 
of Gymnosperms must have had rather closely related ancestors 
derived directly from the eusporangiate ferns. There is little 
probability that the real ancestry will ever be discovered, at least 
not until more progress is made in finding plant remains or im¬ 
pressions of far earlier times than any yet known. The fossil 
history of plants practically begins with the Cordaites, and 
although one may find interesting transition forms between 
* Contribution from the Botanical Laboratory of Ohio State Univer¬ 
sity, No. 73. 
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