BOTANISTS AND DARWINISM. T03 



by any birds. Of the flowering plants there then existed 

 only the two lowest classes, the pines and palm ferns, 

 with naked seeds, whose simple and insignificant blossoms 

 scarcely deserve the name of flowers. 



The phylogeny of Ferns, and of the Gymnosperms which 

 have developed out of them, has been made especially clear 

 by the excellent investigations which Edward Strasburger 

 published in 1872, on "The Coniferse and Gnetaceas," as 

 also " On Azolla." This thoughtful naturalist and Charles 

 Martins, of Montpellier, are among the few botanists who 

 have thoroughly understood the fundamental value of the 

 Theory of Descent, and the mechanical-causal connection 

 between ontogeny and phylogeny. The majority of 

 botanists do not even yet know the important difference 

 between homology and analogy, between the morphological 

 and physiological comparison of parts — which has long 

 since been recognized in zoology — but Strasburger has 

 employed this distinction and the principle of evolution in 

 his " Comparative Anatomy of the Gymnosperms," in order 

 to sketch the outlines of the blood relationship of this 

 important group of plants. 



The class among Ferns which has developed most directly 

 out of the Liverworts is the class of real Ferns, in the 

 nan-ow sense of the word, the Frondose Ferns (Filices, or 

 Phyllopterides, also called Pteridse). In the present flora of 

 the temperate zones this class forms only a subordinate 

 part, for it is in most cases repiesented only by low forms 

 without trunks. But in the torrid zones, especially in the 

 moist, steaming forests of tropical regions, this class presents 

 us with the lofty palm-like fern trees. These beautiful tree- 

 ferns of the present day, which form the chief ornament of 



