288 CHARACTERS OF TRIBES AND GENERA. 



Tribe 21. PTERIDEJ3 (Plate 21). 



Fronds varying- from simple, entire, to decompound mul- 

 tifid, and from 1 to 10 or more feet in height, and (with 

 the exception of Doryopteris) of a thin flaccid texture. Veins 

 free or anastomosing, their apices combined forming a 

 transverse, marginal, sporangiferous receptacle, seated in 

 the axis of an exteriorly attached inflexed special indusium 

 forming oblong or continuous marginal sori. 



OBS. I have already explained under CTieilantlieoe my 

 reasons for separating it from Pteridece, which as now 

 restricted contains about one hundred described species of 

 which the genera Pteris and Litobrochia contain the principal, 

 which technically differ in the venation of the first being 

 free and in the second anastomosed in various ways. 



Sect. 1. Veins anastomosing. 



163. DORTOPTERIS, J. 8m. (1841). 

 Pteris sp. auct., sect. Litrobrochia, Hook. Sp. Fit. 



Vernation fasciculate, erect, rarely sarmentose. Fronds 

 simple, cordate-hastate, or palmately-lobed ; pinnae entire 

 or lobed, smooth, opaque, castaneous, stipes and rachis often 

 ebeneous. Veins internal, reticulated. Receptacles trans- 

 verse marginal, seated in a narrow exterior attached 

 indusium, forming a linear continuous sorus. 



Type. Pteris pedata, Lirni. 



Illust. Hook, and Bauer Gen. Fil., t. 65, B. ; Hook. Fil. 

 Exot., t. 34 ; J. Sm. Ferns Brit, and For., fig. 98. 



OBS. This is a small group of pretty Ferns, with the 

 same general character as regards texture, colour, and 

 smoothness as Pellcea and Cassebeera, but technically distin- 



