CHAPTER XXV. 



_ . , f I. Botryoptereae. 



Coenopterideae. < ■r^ „ ^ . 



^ { II. Zygoptereae. 



The term Botryopterideae, first used by Renault, has been 

 applied to a group of Palaeozoic ferns ranging from the Lower 

 Carboniferous to the Permian and containing several genera, 

 the distinguishing features of which are supplied by the 

 anatomical structure of the stems or, in many cases, by that 

 of the petiolar vascular strand. Scott ^ subdivides the Botryo- 

 pterideae into the Botryopteris and the Zygopteris sections. In 

 an admirable monograph recently published by Paul Bertrand^ 

 considerable changes are proposed in current nomenclature ; he 

 substitutes the name Inversicatenales for Botryopterideae, a 

 designation, which as Scott remarks, is " probably too technical 

 to command general acceptance." A more serious criticism is 

 that the name Inversicatenales has reference to a character 

 (the inverse curvature of the leaf-trace in relation to the axis 

 of the stem) which is by no means universal in the group^ 



In the following account, necessarily incomplete, the generic 

 terminology of Bertrand is adopted, but this decision does not 

 carry with it any obligation to accept the name Inversicatenales. 

 We may speak of the types of Palaeozoic ferns dealt with in 

 the following pages as members of a group differing in many 

 respects from any existing genera of the Filicales, and ex- 

 hibiting the characteristics associated with generalised plants. 

 Williamson, as early as 1883, spoke of Renault's Botryopte- 



» D. H. Scott (08). 2 P. Bertrand (09). s Scott (09^). 



