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the uncovering of this singular group, because the greatest deposits are 

 in this country. The work of Wieland in revealing the rich deposits of 

 these plants in the Black Hills region and in sectioning the cones with 

 admirable skill and patience is well known. For the last five months 

 Wieland has been exploring southern Mexico, and has discovered a sec- 

 tion 2,000 feet in thickness that is packed with the remains of this pe- 

 culiar group, making it undoubtedly the greatest deposit of these plants 

 in the world. They are regarded now as of great interest because the 

 peculiar structure of their cones has suggested the possibility that they 

 may be a group of gymnosperms that has given rise to angiosperms. 



Perhaps another notable change that deserves mention is the practical 

 demonstration of the relationship between the two groups of angiosperms. 

 It was thought ouce that the monocotyledons were the more primitive 

 angiosperms. and that the dicotyledons were the more recent. We feel 

 assured now that the monocotyledons have been derived from dicotyledons, 

 for every monocotyledon starts with the vascular system of a dicotyledon ; 

 and if there is anything true in the old theory of recapitulation, the rela- 

 tionship of these two groups is evident. 



Perhaps the most notable change in morphology is the change in men- 

 tal attitude, and particularly in reference to the construction of phy- 

 togenies. I remember that at the early meetings of this Academy we were 

 in the habit of constructing very complete and satisfactory phylogenies. 

 We were sure just how one plant group descended from another. That is 

 always easy when the facts are few ; but now that facts are numerous, 

 no one is able to construct a satisfactory phytogeny. No one imagines now 

 that any living group has descended from any other living group. 



Another marked advance is the change of mental attitude in connec- 

 tion with morphological work, in which morphology has clasped hands 

 with physiology. I can only indicate some of its results. It has destroyed 

 the old rigid categories. Botany was once largely an extensive system 

 of terminology. Xow we have passed from the days of terminology to 

 the days of knowledge, and terminology no longer masquerades as knowl- 

 edge. Not one of the old definitions has stood the test of experimental 

 morphology. Experimental morphology has also helped to rid us of thai 

 old, Calvinistic notion <>f predestination in plant organs. Once it was 

 thought that every primordiuni was destined to be one particular structure 

 nnd nothing else. Now we know that a primordiuni may become almost 



