CHAPTER V 



FOSSIL GYMNOSPEBMS 



THE numerous fossil remains, from the early Paleozoic 

 onward, which have been referred to Gymnosperms, have been 

 determined chiefly by their anatomical features. This result 

 has come from the nature of the available material, but to the 

 morphologist it is suggestive rather than demonstrative. A vast 

 amount of material has been named, which has been made some- 

 what available for the morphologist by Solms-Laubach, 3 and 

 most recently by Scott. 6 Unfortunately, at this writing the 

 second volume of Seward's Fossil Plants, which will deal with 

 Gymnosperms, has not appeared. In any consideration of the 

 phylogeny of Gymnosperms the historical point of view is abso- 

 lutely essential, and in so far as there are any real morphological 

 data among paleobotanical material they must be considered in 

 the present connection. 



Paleobotanists have recognized a group of fossil forms inter- 

 mediate between Ferns and Cycads, to which Potonie has given 

 the name Cycadofilices. They were especially abundant during 

 the Carboniferous, and many of them have been described as 

 Ferns. Some of the characteristic forms included in this pro- 

 posed intermediate group are Heterangium, Lyginodendron, 

 and Medullosa. The testimony in reference to the position of 

 these forms is entirely anatomical, but it is extremely suggestive 

 of the intermediate position claimed for the group by most paleo- 

 botanists. The historic evidence seems to be clear that the 

 paleozoic Ferns merged gradually into the Cycads. 



In addition to these transition forms, concerning which the 

 morphologist must hold his judgment in suspense until the more 

 essential structures have been discovered, there are certain ex- 

 tinct groups whose Gymnosperm character is undoubted. 

 Among them the most conspicuous are the Cordaitales. 

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