2150 A TEXTBOOK OF THEORETICAL BOTANY 



4. Lycopodioles Lepidophytineae 



a, Lycopodiales Eligulatae 5. Psilotales 



p. Lycopodiales Ligulatae 6. hoetales 



Selaginellineae 7. Cycadofilices 



Shortly after this had appeared it became known that the members of 

 the Cycadofilices bore seeds, so this group was transferred, with some 

 doubt, to the Gymnospermae. Botanists were not, however, truly happy 

 about this change and we find in 1909 that Lotsy, impressed by the signi- 

 ficance of leaf shape and size, adopted the valuable terms Lycopsida, 

 for the types with small leaves, and Pteropsida, for those with relatively large 

 ones. These terms had been introduced by JeflFrey in 1902, but that author 

 did not embody them in a detailed classification. The latter term is applied 

 beyond the limits of the Pteridophyta, as the following scheme will indicate. 



A. Lycopsida B. Pteropsida 



1. Sphenophyllales i. Filicales 



2. Equisetales 2. Cycadofilicales (Pterido- 



3. Psilotales spermae) 



4. Lycopodiales 3. Gymnospermae 



4. Angiospermae 



In 1910 the first of four volumes on " Fossil Plants " was published by 

 Seward. Though primarily, as the title suggests, concerned with fossils, 

 Seward tried to incorporate the extinct Pteridophytes into the framework 

 of a general classification of the Pteridophyta. The outline of this classifica- 

 tion was as follows: 



1. Equisetales 5. Filicales 



2. Sphenophyllales a. Leptosporangiatae 



3. Psilotales p. Marattiales 



4. Lycopodiales y. Ophioglossales 

 a. Homosporeae 8. Hydropterideae 

 p. Heterosporeae 



He recognized the Coenopterideae as a group of fossil ferns, which he 

 subdivided into the Botryoptereae and the Zygoptereae, but he did not 

 indicate definitely what he considered to be their relationship with the rest 

 of the Filicales. Meanwhile Scott had also published a volume on Fossil 

 Plants in 1900 in which he gave descriptions of all the then known forms. 

 This work passed through three editions under the title of " Studies in 

 Fossil Botany", the last edition appearing in 1923. 



The year 1913 saw the first description of the Rhyniaceae by Kidston 

 and Lang and the subsequent introduction of the Psilophytales as a further 

 class of the Pteridophyta. Meanwhile Campbell, in his book the " Euspo- 

 rangiatae", and Bower (Fig. 2063), in a series of publications, ending in 

 his great work " The Ferns", which appeared in three volumes between 

 1923 and 1928, did much to revise the classification of the FiUcales on the 



