424 STUDIES IN FOSSIL BOTANY 



Leaves filicoid (Sphenopterid or Pecopterid). 



Stem monostelic ; leaf-trace and main foliar bundle 

 single or double, concentric in the petiole. Xylem 

 mesarch. 



Reproductive- organs borne on somewhat modified 

 pinnae of the frond. 



Microsporangiate organs of the Crossotheca type. 



Seeds with radial symmetry, of Cycadean type, with 

 nucellus adherent to integument, and with a single 

 vascular system. Seed or seeds often enclosed in a 

 cupule. 



The relations of the Lyginodendreae to other groups 

 will be further discussed at a later stage. 



