THE PALEONTOLOGIC RECORD 67 



THE KELATION OP PALEOBOTANY TO PHYLOGENY 



BY PBOFESSOR D. P. PENHALLOW 



MCGILL UNIVERSITY 



THE history of plant life has been the central idea in all botanical 

 studies from the very earliest times, whether expressed in the 

 imperfect methods of the early German and Dutch botanists who de- 

 sired simply to establish natural affinities on the basis of external re- 

 semblances, or in the ambitions of Csesalpino to arrive at a classifica- 

 tion of plants which should satisfy the conditions of relationship 

 through the structure of all parts, and especially of the reproductive 

 organs. For nearly four hundred years the external organs have been 

 employed as the chief basis of those numerous systems of classification 

 which have appeared from time to time. The idea that the reproduc- 

 tive organs and the minute interior structure of plants were of primary 

 importance as first advocated by Caesalpino, was for a long time lost to 

 view, although it reappeared now and then in the works of later writers. 

 Eventually it gained recognition and became a factor of increasing im- 

 portance, until the most advanced systems now employed involve an 

 acceptance of both the external parts and the internal anatomy as es- 

 sential factors. 



From the time of Malpighi and Grew, to Goeppert and Corda, our 

 knowledge of the interior structure of plants made great and rapid 

 progress, and was later applied successfully by various investigators in 

 the direction of establishing relationships. To no one are we more 

 fully indebted for an elaboration of this idea than to Williamson, whose 

 researches into the structure of fossil plants from the Coal Measures 

 of Great Britain, during the latter part of the last century, laid the 

 real foundation of modern paleobotany. 



In so brief a treatment as that which is now employed, it is impos- 

 sible to more than touch upon some of the salient features in the rela- 

 tions of paleobotany to the course of phylogeny, but it is, nevertheless, 

 tforth while to give special emphasis to the now well-recognized fact 

 that a thorough knowledge of the interior structure of the plant, and 

 especially of the stem, leads to a more comprehensive and exact ac- 

 quaintance with relationships than that of any other part. This arises 

 from the fact that the minute anatomical details have a greater degree 

 of stability than any other portion of the body, doubtless due to the fact 

 that in its adjustment to the land habit, the environmental influences 



