378 GENERA OF FERNS. 
Province of Pernambuco, Gardner n. 2911, Serra Acurua, 
Province of Bahia, Blanchet n. 2859. 
RuIzOBOLACEZ, 
780. Anthodiscus trifoliatus, G. F. W. Mey. Prim. Fl. 
Esseq. p. 194. Benth. in Trans. Soc. Linn. Lond. v. 18, p. 237; 
t. 20.—On the Essequibo and Rupunoony, Schomburgk 
n. 512. 
(To be continued.) 
An Arrangement and Definition of the Genera of Ferns, with 
observations on the affinities of each genus. By J. Smith, 
A.L.S. 
(Continued from p. 668. of vol. 1.) 
Div. IL. GLEICHENIACES. R. Br. 
Sporangia globose or pyriform, usually compressed on their 
interior side, unilocular, sessile, opening vertically, furnished 
with a complete transverse ring. Sori round, superficial or 
immersed, naked or furnished with indusioid hairs. 
Obs. In my remarks under Cyathee, I have shown that the 
direction of the ring is not, in certain cases, worthy to be 
adopted as a primary character; and although the form and 
sessile attachment of the sporangia of Gleicheniacee, may also, 
to a degree, influence the direction of the ring, as in Cyathee 
and Hymenophyllee, still, with regard to this family, it must not 
be too strictly viewed as a structure of little value. Even 
setting aside the difference in structure of the sporangia, the 
very distinct habit of Gleicheniacee is of itself sufficient to 
warrant us in keeping them separate from Polypodiacee. They 
cannot be naturally associated with any genus of ferns, ex- 
cept, indeed, Matonia, which genus has several characters in 
common with the present group, especially its general habit, 
and the sori being composed of a definite number (few) of 
sessile sporangia. Thus it has become a question with me 
whether it would not be more natura) to consider Matonia 
