2$0 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 PTEROPSIDA 



Without seeds Ferns 5 



With seeds SPERMATOPHYTA (PHANEROGAMS) Seed Plants 6 



Ovules naked, endosperm formed before fertilization . Gymnos perms 6 



Sperms ciliated Early Gymnosperms 6a 



Sperms not ciliated Lale Gymnosperms 66 



Ovules enclosed, endosperm formed* after fertilization . A ngios perms 6c 



3. Clubmosses (Lepidophyla (Bessey)) 

 Lycopodiales Selaginellales 

 Isoetales (?) Lepidodendrales (Fossil) 

 Psilotales 



4. Horsetails (Calamophyta (Bessey), Sphenopsida (Scott), Arthro phyla 



(Berry)) 



Spenophyllales (Fossil) - Calamariales (Fossil) 



Pseudoborniales (Fossil) Equisetales 



5. Ferns (Pterido phyla, in restricted sense; Filicinea). 

 Eusporangiata Leptosporangiata 



Primofilices (Coenopteridese) Osmundales 

 Marattiales Polypodiales 



Ophioglossales Marsiliales 



(Isoetales?) 



6. Seed-Plants 



(6a & 6b Gymnospermce of Brongniart) 



6a. Early Gymnosperms (Cycado phyla (Nathorst) except Ginkgoales; 



Archigymnospermce (Jeffrey)) 



Cycadofilicales (Fossil) Cordaitales (Fossil) 



Hemicycadales (Wieland) = Ginkgoales 



Bennettitales of Potonie (Fossil) 

 Cycadales 



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

 frey); Sir obtto phyla (Bessey)) 

 Taxales Finales 



Araucariales Gnetales 



