CYCADOFILICALES 



CYCADOriLICALES 



The Carboniferous period was once called the "Age of Ferns" on 

 account of the numerous impressions of fernlike leaves; but most of 

 these leaves are now known to belong to seed plants which looked 

 like ferns. Seed ferns would seem to be a 

 good vernacular name for the group, and 

 our British friends simply translate it into 

 Pteridosperms. We object to the name be- 

 cause it sounds and looks as if it were co- 

 ordinate with gymnosperms and angio- 

 sperms. The angiosperms have their seeds 

 enclosed in a chamber, usually called the 

 "ovary"; while, in the gymnosperms, the 

 seeds are naked, not at all enclosed in any 

 chamber. In the Cycadofilicales the seeds 

 are naked, and, consequently, the forms are 

 genuine gymnosperms and cannot be sepa- 

 rated from them on the basis of characters 

 as important as those which separate gym- 

 nosperms from angiosperms. 



Williamson, Scott, and others described 

 stems with characters intermediate between 

 ferns and cycads and, in 1899, Potonie pro- 

 posed the name "Cycadofinces" to indicate 

 the composite character. In 1903, Oliver 

 and ScoTT'*^^ found that the seed, Lagenosto- 

 ma, belonged to the stem, Lyginodendron, 

 and thus initiated a series of investigations 

 which has resulted in linking up scattered 

 seeds, stems, and leaves, until most of the 

 plants which gave the Carboniferous the 

 name, "Age of Ferns," are now known to be seed plants. This 

 assembling of scattered parts recalls the earlier assembling of 

 scattered stages in the life-history of wheat rust. 



In the Cycadofilicales the most complete assembling has been the 

 one started by Oliver and Scott when they found that the seed, 

 Lagenostoma, and the stem, Lyginodendron, belonged together. 



CyCADOPHyJE CONIFEROPHYTC 



Fig. 3. — Diagrammatic 

 illustration of the habit 

 and comparative size of 

 members of the Cycado- 

 phytes and Coniferophy tes. 

 • — From Chamberlain's 

 Elements of Plant Science 

 (McGraw-Hill Book Co.). 



