NOTABLE FERN FAMILIES 



OSMUNDA (Flowering Ferns) 



Tall swamp ferns, growing in large crowns, with the fertile fronds 

 or portions conspicuously unlike the sterile ; sporangia opening by 

 a longitudinal cleft into two valves. 



ONOCLEA 



Coarse ferns, with the fertile fronds rolled up into necklace- 

 like or berry-like segments, and entirely unlike the broad, pin- 

 natifid sterile ones. Fertile fronds unrolling at maturity, allowing 

 the spores to escape, and remaining long after the sterile fronds 

 have perished ; sporangia stalked, ringed, bursting transversely. 



WOODSIA 



Small or medium-sized ferns, growing among rocks, with 1-2 

 pinnate or pinnatifid fronds and round fruit-dots ; indusium thin 

 and often evanescent, attached by its base under the sporangia, 

 either small and open, or else early bursting at the top into irregular 

 pieces or lobes ; sporangia stalked, ringed, bursting transversely. 



CYSTOPTERIS (Bladder Ferns) 



Delicate rock or wood ferns, with 2-3 pinnate fronds and round 

 fruit-dots ; indusium hood-like, attached by a broad base to the in- 

 ner side, soon thrown back or withering away ; sporangia as above. 



ASPIDIUM (Shield Ferns) 



FernS with 1-3 pinnate fronds and round fruit-dots; indusium 

 more or less flat, fixed by its depressed centre ; sporangia as above. 



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