chap, iv Taxonomy, 1860-1900 121 



When we turn to the systematic position of the Gymno- 

 sperms we see that, while in i860 they were considered to be 

 a subdivision of the Phanerogams, and hence not on the 

 same plane as the Vascular Cryptogams, opinion gradually 

 changed as the century closed, and they came to be regarded 

 as co-ordinate with the Pteridophyta, and on the whole 

 more nearly allied to them than to the Angiosperms. Their 

 relationship to the former group was supported by Belajeff's 

 researches on the germination of their pollen in 1891-93, 

 in the course of which he was led to the recognition of 

 an antheridium of a higher type than had been previously 

 observed. A more striking indication of affinity was 

 afforded by the discovery of ciliated antherozoids in 

 Ginkgo by Hirase in 1895, in Cycas, by Ikeno, in 1896, 

 and in Zamia, by Webber, in 1897. 



In studying the phylogeny of the group a safe starting- 

 point was afforded by Hofmeister's classical researches, 

 which clearly indicated a descent from some form of 

 Pteridophytic stock. From the similarity between the 

 gametophytes of the Conifers and of Selaginella, as well 

 as from the similarity of the general habit of the sporophyll 

 in the Coniferae and the Lycopodinae, it was considered that 

 theGymnosperms descended fromLycopodiaceous ancestors. 

 The relationship was considered to be supported by the 

 presence of gigantic members of the latter group in the 

 carboniferous rocks. The idea, however, of a monophyletic 

 descent was gradually abandoned as more and more informa- 

 tion was obtained from fossil forms. The study of the latter 

 was prosecuted with considerable energy during the last 

 decade of the century, and brought to light many con- 

 siderations bearing upon affinity and descent. 



The careful scrutiny of the structure of Heterangium 

 and Lyginodendron by Williamson and Scott pointed to 

 a relationship with both the Cycads and the Ferns, an 

 idea supported by the study of the members of the Lygino- 



