124 CHARACTEKi Or TRIBES AND GENERA. 



Sp. P. alcicorne {Sw.) (v v.) ; P. Stemmaria (Desv.) (v v.) 

 (■P. JUtMoincum, Hook. Gard. Ferns, t. 9) ; P. grande 

 {J. Sm.), Hook. Fil. Exot., t. 86 ; Bedd. F. Brit. Ind., pi. 

 S26 ; p. biforme {Bl. Fil. Jav., t. 18) (v v.) ; Bedd. F- 

 Brit. Ind., pi. lOi) ; P. Wallicliii {Hook. Fil. Exot., t. 97), 

 (v V.) ; Bedd. F. Brit. Ind., pi. 108.* 



Obs. — In Queensland P. grande grows to a large size on 

 trees. The barren fronds overlapping each other, and 

 forming a round or oblong convex mass, 2 to 3 feet in 

 diameter, and as much high ; which often becomes so sur- 

 charged with water, that the whole mass in time falls to 

 the ofround. 



Division II.— DESMOBRYA. 



Vernation terminal, adherent, uniserial, or fasciculate. 



I. Bing of Sporangia vertical. 



Tribe 6.— ACEOSTICHE^-E (Plate 6). 



Fronds dimorphous, the fertile wholly or some portion of 

 it contracted. Veins obscure. Sori amorphous. 



Obs. — This tribe is composed of species of the genua 

 Acrosiichum, of Linnseus, Swartz, and other authors, as 

 now restricted, the number of described species being about 

 140t They vary greatly in size and in the circumscription 

 of their fronds, which, with the difference of their vernation 

 and venation, afford sufficient characters to admit of the 



* In the Gardeners' Chronicle, March 6th, 1875, Mr. T. Moore 

 described a new bpecies under the name of P. Willinickii, a native of 

 Java. Its fructification is terminal, on narrow segments like that of 

 P. alcicorne. 



+ In the Appendix to " Syn. Fil." forty additional species are 

 enumerated. 



