Fig. 21: 1 and 2, Dryopteris cristata: 1, frond and rhizome, X %; 2, enlarged 

 pinna, X 3. 3 and 4, Dryopteris ludoviciana: 3, pinna, X %; 4, detail of pinnules, 

 X 3. (From Correll in Lundell's Flora of Texas, Vol. 1, PI. 33). 



