Fig. 19: 1 and 1, Thelypteris hexagonoptera: 1, frond and rhizome, X %; 2, seg- 

 ment with sori, X 3; 3a-3c, Thelypteris palustris var. Haleana: 3a, pinna, X %; 3b, 

 sterile segment, X 3; 3c, lower surface of fertile segment, X 3. 4-5b, Cvstopteris 

 jragihs var. protrusa: (not usually considered a wetland plant) 4, frond and rhizome, 

 X %; 5a, segment with sori, X 3; 5b, sorus, X 25. (From Correll in Lundell's Flora 

 of Texas, Vol. 1, PI. 35). 



