No. 535] NOTES AND LITERATURE 



447 



on the latter. Whether or not we admit the relationship of 

 Ophioglossum with these ancient ferns, there is no question that 

 hoth in regard to the early history of the sporophyte and in the 

 structures of the adult sporophyte. Ophioglossum most nearly 

 represents among living ferns what we may fairly assume to 

 have been the primitive type from which the higher ferns have 

 sprung. 



In view of the abundant evidence of the primitive nature 

 shown by the living Ophioglossacea\ we can not believe that 

 these plants did not exist in the earlier geological epochs; and 

 the failure to record them is due either to the complete disor- 

 ganization of their delicate tissues, or to a failure by investiga- 

 tors to recognize the ferns allied to them which may have been 

 found in a fossil state. 



Dr. Scott in his second volume gives an excellent account of 

 the Cordaitales and the Cycads, but it is to be regretted that his 

 treatment of the Conifers is so brief. He explains this by stating 

 that the present knowledge of the fossil Conifers is not suffi- 

 ciently exact to make a satisfactory general treatment feasible. 

 It is to be hoped that in the concluding part of Professor Sew- 

 ard's treatise they will receive adequate attention. 



The Cordaitales, the earliest known seed plants and com- 

 pletely extinct at the present time, are remarkable for the per- 

 fection with which their floral structures, as well as their vege- 

 tative tissues, have been preserved. They evidently represent a 

 more or less synthetic type with apparent connections with sev- 

 eral of the other great groups, but their exact place in the 

 system is still not quite satisfactorily settled. 



The advance in our knowledge of the 1 1 Cycadophytes " — the 

 Cycads and their relations — during the past ten years has been 

 very great, largely due to the labors of an American paleobotan- 

 ist, Dr. Wieland. 3 His remarkable studies on the wonderfully 

 preserved Mesozoic Cycads of the Black Hills Region of South 

 Dakota and Wyoming, form one of the most notable contribu- 

 tions to fossil botany that have been made for many years. 

 These Mesozoic Cycads are separated from the recent type of 

 Cycads as a distinet family, the Benettiteae or Cycadeoidea?. It 

 is the floral structures of these plants that have attracted the 

 greatest attention, as they show a curious similarity in their gen- 

 eral structure to such a flower as a magnolia, although they are 

 gymnosperms. This resemblance is so striking that some stu- 



* Wieland, G. K., "American Fossil Cycads," Carnegie Institution of 

 Washington, Publication No. 34, 1906. 



