CHARACTERS OF TRIBES AND GENERA. 123 



the sterile, once or many times dichotomously forked, 2 to 

 6 feet in length ; segments broad, obtuse, densely covered 

 with stellated scales, coriaceous. Veins internal, compound 

 anastomosing. Receptacles amorphous, occupying more or 

 less of the under side of the segments, or on a sessile or 

 petiolate lobe, forming dense masses of sporangia. 



Type. Acrostichum alcicorne, Swartz. 



Illust. Hook and Bauer, Gen. Fil., t. 80 B. ; Moore Ind. 

 Fil., p. 9. B. ; J. Sm., Ferns, Brit, and For., fig. 46 ; 

 Hook., Syn. Fil. t. 8, fig. 61. 



OBS. The whole habifc and character of the species 

 forming this genus is very peculiar, and totally distinct 

 from any other genus of Ferns, but agreeing in the amor- 

 phous production of the sporangia with Acrostichum, but 

 although the axis of the vernation is scarcely defined, 

 it nevertheless exhibits the articulate node of Eremo- 

 brya. I therefore place it in this division. The thick 

 coriaceous texture, and the stellated pubescense, show 

 some analogy to Niphobolus. Besides its peculiar habit, 

 the sporangiferous receptacle also presents a structure 

 peculiar to this genus, being formed of an accessory layer 

 of minute veinlets, which appear independent of the vas- 

 cular structure. 



Five species are described as belonging to this genus, 

 which until lately were considered to be entirely natives of 

 the tropics and extra tropics of the Eastern hemisphere, 

 extending from Western Tropical Africa through the 

 islands of the Indian Ocean, Malayan, Philippine, and other 

 islands in the Eastern Pacific, as also the eastern coast of 

 Australia, extending to about the latitude of Sydney. This 

 wide eastern range is not now special, Mr. Spruce having 

 recently discovered P. alcicorne at Tarapota, in the Andean 

 regions of Brazil. 



