1f. Ferns or leafless plants with three angled stems A. Plants bearing scalelike "leaves" or appendages but appearing leafless from a short distance ........ Psilotaceae Psilotum nudum (L.) Griseb. AA. Plants bearing fronds --- Polypodiaceae B. Fruiting bodies borne in clusters (sori) arranged in dots, lines, or larger areas on the lower sur- face 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 D. Sori round or broad oblong Fronds jointed to rootstock Polypodium DD. Sori narrow, straight or curved E. Sori parallel to the midrib, con- tinuous; fronds once or twice pin- nate Plants without trunk; fronds 8- 18 in. ..... Blechnum EE. Sori more or less oblique to mid- rib; fronds entire; ea. sorus with one cover which opens from the upper side ... Asplenium