The Ohio ^ACaturalist, 



PUBLISHED BY 



The Biological Club of the Ohio State Uni'versity, 



Volume XIII. APRIL, 1913. No. 6. 



TABLE OF CONTENTS. 



ScHAFFNER— The Classification of Plants, IX 101 



McAvoY— Liliales of Ohio 109 



Brain— A Preliminary List of the Acarina of Cedar Point 131 



McLellan— Meeting 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 Podocarpaceffi 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 Gymnospemis 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 earher 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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