Ferns or leafless plants with three angled stems 
A. Plants bearing scalelike "leaves” or appendages but appearing 
leafless from a short distance...*... Psilotaceae 
Psilo tum nudum ~Tl) Griseb. 
AA. Plants bearing fronds 
Polypodiaceae 
B. Fruiting bodies borne in clusters (sori) arranged in dots, 
lines, or larger areas on the lover surface of the frond; 
plant growing on the ground or some on supports; fertile 
and sterile fronds similar 
C. Tip of frond coiled at maturity. Nephrolepis 
CC. 
Tip of frond not coiled at maturity 
