- 270 CHARACTERS OF TRIBES AND GENERA. 
Tribe 9 -CERATOPTERIDEZ (Plate 9). 
This tribe consists of one species only, originally named 
by Linnsus Acrostichwm thalictroides, and by later botanists ` 
it has been characterised under no less than nine different 
generic and a dozen specific names. 
79.—CERATOPTERIS, Brongn, (1821). 
Ellobocarpus, Kaulf.; Parkeria, Hook. 
Vernation fasciculate, erect, acaulose (plant annual). 
Fronds fragile; the fertile decompound ; segments forked, 
linear; margins revolute, membranaceous, conniving, 
induseform. Veins transversely elongated, distantly anas- 
tomosing. Sporangia occupying the transverse venules, 
superficial, large, disposed in a simple series, constituting 
two linear sub-parallel sori. 
Type. Ceratopteris thalictroides, Brongn. 
Illust. Hook. and Bauer, t. 12 ; Moore Ind. Fil., p. 94 A. ; 
J. Sm. Ferns Brit. and For., fig. 60; Hook. Syn. Fil., 
t. 3, fig. 32. 
Oss.—This genus is founded on a very remarkable and 
peculiar Fern, being one of the few that are annual. It is 
found widely spread in the tropies of both hemispheres, 
growing in wet places or even in shallow water, the sterile 
fronds floating on the surface, and being viviparous, and with 
the ready germination of the numerous spores, and rapid 
growth of the fronds, makes it abundant in the places of its 
growth. Besides the special habit of the plant, the sporangia 
exhibit a peculiar structure, being large globose, and either 
furnished with a broad nearly vertical or short imperfect 
ring, which is described by some authors as horizontal, | d 
and consequently has led Ceratopteris to be associated with — 
