235 



prepared their great work, Genera Plantanim (i 862-1 881). It 

 describes with great detail all genera of seed plants, "the greater 

 portion," Hooker writes, "being the product of Bentham's 

 indefatigable industry." The arrangement is in the main that of 

 de Candolle, the main divisions being: 



DicoTYLEDONES (Polypctakie, Gamopetalae and Monochlamy- 

 deae) . 



G V.M XOSPE RiM EAE . 

 MOXOCOTYLEDONES. 



It is interesting to note that while in the text gymnosperms are 

 implied to be included in dicotyledons, in the list of contests 

 the\- are put up as a separate group. Bentham and Hooker's 

 system was followed in Gray's "Manual," including the sixth 

 edition. There gymnosperms are retained under dicotyledons, 

 but the interesting suggestion is made that it would be more 

 natural to place endogens at the beginning, that is, dicotyledons 

 between monocotyledons and gymnosperms. 



Eichler's studies on the structure of flowers made more definite 

 groups of related families, now called orders. His classification 

 was a combination of previous systems, thus: 



r Thallophyta 

 Crvptogamae \ Bryophyta 



[ Pteridophyta 



Gymnospermae 



r Monocotyleae 

 Angiospermae •< Dicotyleae (Choripetalae 

 [ and Sympetalae) 



Phanerogamae 



The Choripetalae begin with catkin-bearing trees and end with 

 the pea family; the Sympetalae end with the composites. The 

 last family with its condensed inflorescence, united petals and 

 anthers, and inferior ovary, is considered as the culmination of 

 evolution of the dicotyledons. 



Die Natiirlichen Pflanzenfamilien, the great cooperative work 

 edited by Engler and Prantl, appeared in the last decade of the 

 nineteenth century and is as yet the most complete exposition of 



