Sporangia dorsal, not gathered in sori, scattered irregularly on the few 

 longitudinal veins of the fertile fronds. Indusium wanting, but the margin 

 of the fertile fronds hroadly recurved, hardly changed in texture, the ed- 

 ges meeting against the midribs, quite enclosing the capsules when young. 

 Ring vertical, broad, incomplete, short or interrupted by the very short, nearly 

 wanting stalk of the capsule, wanting in the american form. Stomium 

 transversal. 



Rhizome short, erect. Fronds divided, rather dimorphous; veins anas- 

 tomosing, but more copiously in the barren than in the fertile fronds. 



' Pantropical; in quiet, shallow waters, or even dry ground in humid re- 

 gions or during the rains. 



No. 87. Ceratopteris. 



ST. CEIfc^^TOPTEItlS, nrongniart. 



Characters of the family. 



* C thalictroides, Brong., Rac, Flor. Btz., I, 165; Hk. Bk., 

 Syn. Fil., tab. Ill, fig. 32; Diels, in Engl. & Prantl, Nat. Pfl. Fam., P, fig. 

 178—179; Bau. k Hk., Gen. Fil., tab. XII; Bedd., Ferns S.I., tab. LXXV; 

 Parkeria pteridioides, Hk., Exot. Flor., II, tab. CXLVII; Hk. & Grev., Ic. 

 Fil., tab. XCVII; Acrosiichum thaliclroides, L., (oldest name). 



Rhizome erect. Stipes tufted, thick, succulent, filled with large air-cells, 

 naked, 5 — 20 c.M. long. Barren fronds floating or erect, 2 — 5-pinnatisect 

 with linear or lanceolate ultimate segments 1 — 7 c.M. long; fronds of the 

 young plants simple or slightly incised. Texture flaccid, succulent; surfaces 

 naked; veins anastomosing copiously and irregularly. Fertile fronds with the 

 segments narrowlinear, pod-like, the veins few, distantly anastomosing, run- 

 ning down the frond longitudinally. — Parkeria pteridioides, Hk. is the ame- 

 rican form with exannulate capsules. 



Pamtropical. 



