CHARACTERS OF TRIBES AND GENERA. ` 199 
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. 
Ilust. 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. 
Oss.—The whole habit 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 
eu 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 
SC of minute veinlets, which appear independent of the vas- 
. eular 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, - 
2 extending from Western Tropical Africa through the 
islands of the Indian Ocean, Malayan, Philippine, and other - 
a islands in the Eastern Pacific, as also the eastern coast of 
Po 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. 
