Ferns of British India and Ceylon. 123 



(Also in West tropical Africa, the East African Islands, Queens- 

 land, the Philippines, and Polynesia.) 



GENUS XXXIL— CERATOPTERIS. (Brong.) 



(Kerns, keratos, a horn ; pteris, a fern: the horned fern.) 



Sori placed on two or three distantly anastomosing veins which run 

 down the frond longitudinally, and are parallel both with the edge 

 and midrib ; veins of the sterile fronds articulated in oblique oblong 

 hexagonal areoles. Capsules scattered on the receptacles, sessile, 

 subglobose, with a ring which is either complete or more or less 

 partial or obsolete. Indusium formed of the reflexed margin of the 

 fronds, those of the two sides meeting against the midrib. A very 

 anomalous genus, regarded by some as a distinct order ; it is very 

 unlike Pterideae, and should be placed in a distinct tribe. 



1. Ceratopteris thalictroides. (Lin.) Stipes tufted, thick 

 inflated, filled with large air-cells ; fronds succulent in texture, the 

 barren ones floating or erect, simple or slightly divided when young, 

 bi-tripinnate with narrow linear segments when mature, fertile ones 

 bi-tripinnate ; ultimate segments podlike. Hook. Syn. Fil. p. 174. 

 Bedd. F. S.I. t. 75. Acrostichum thalictroides, L. Sp. PI. 1527. 



Throughout India, Ceylon, and the Malay Peninsula up to 

 3,000 feet elevation; common in tanks, ditches, and swampy places, 

 or even dry ground during the rains. Mr. J. Smith says it is an 

 annual, but I do not think it is so in cultivation, if kept in water 

 or very moist, as I had the same plant growing for some years at 

 Ootacamund. 



(Also in the tropics of the whole world.) 



