250 HEREDITY AND EVOLUTION IN PLANTS 



3-5, Vascular Cryptogams 

 Stem smooth, leaves spirally arranged, sporangia single. Clubmosses 3 

 Stem with ridges and joints, leaves whorled, sporangia 



several Horsetails 4 



Woody cylinder discontinuous (i.e., with foliar gaps), 

 leaves large, sporangia below — Pteeopsida 



Without seeds Ferns 5 



With seeds — Spermatophyta (Phanerogams) Seed Plants 6 



Ovules naked, endosperm formed before fertilization . Gymnosperms 6 



Sperms ciliated Early Gymnosperms 6a 



Sperms not ciliated Lale Gymnosperms 6b 



Ovules enclosed, endosperm formed after fertilization . Angiosperms 6c 



3. Clubmosses {Lepidophyta (Bessey)) 

 Lycopodiales Selaginellales 

 Isoetales (?) Lepidodendrales (FoisU) 

 Psilotales 



4. Horsetails (Calamophyta (Bessey), Sphenopsida (Scott), Arthrophyla 



(Berry)) 

 SpenophyUales {Fossil) Calamariales (Fossil) 



Pseudoborniales (Fossil) Equisetales 



5. Ferns (Pteridophyta, in restricted sense; Filicinea). 

 EusporangiatcB Leptosporangiatce 



Primofilices (Coenopteridese) Osmundales 



Marattiales Polypodiales 



Ophioglossales Marsiliales 



(Isoetales?) 



6. Seed-Plants 



(60 &• 6J Gymnospermce of Brongniart) 



6a. Early Gymnosperms (Cycadophyta (Nathorst) except Ginkgoales; 



Archigymnosperma (Jeffrey)) 

 Cycadofilicales (Fossil) Cordaitales (Fossil) 



Hemicycadales (Wieland) = Ginkgoales 



Bennettitales of Potonifi (Fossil) 

 Cycadales 



6b. Late Gymnosperms (Coniferse (Hallier); Metagymnospermae (Jef- 

 frey); Strobilophyta (Bessey)) 

 Taxales Finales . , 



Araucariales Gnetales 



