CHARACTEES OF TEIBES AND GENERA. 255 



distiiig-uished by the sori being terminal and marginal, as 

 also by the fronds before evolution being densely orini- 

 ferous, the hairs being long and articulated, thus differing 

 from Cijatliea, which instead of hairs, are furnished with 

 squamte. 



Sp. D. arborescens, L'Herit. {v v.) ; D. chrysotricha, 

 Moore. {Balanimm, Hassk.) ; D. sqnarrosa, S'li:. (v v.) ; 

 D. fibrosa, Goleiiso ; D. Sellowiana, Hook (v v.); D. 

 Berteroana, Hook ; D. lanata, Col. ; D. Toungii, G. Moore 

 (v v.). 



137.— CiDOTrcM, Kcmlf. (1824) 

 DicJcsonia, sect. Gihotium, HooJc, Sp. Fll. 



Vernation fasciculate, decumbent or erect, and arbores- 

 cent, densely criniferous. Fronds bipiunate, 6 to 15 feet 

 long ; pinnules bipinnatifid, generally glaucous beneath. 

 Yeins simple, forted or pinnate, venules free. Receptacles 

 punctiform, terminal. Indiisimn bivalved, horny, the outer 

 valve (accessary indusium) concave, cucuUate, adnate to the 

 margin ; the inner (siDCcial indusium) smaller, and con- 

 niving- with the outer, forming an unequal bivalved box- 

 like cyst. 



Type. DicJcsonia glauca, Smith. 



Illust. Hook, and Bauer, Gen. Fil., t. 25 ; Moore, Ind. 

 Fil., p. 78 B. ; J. Sm., Ferns, Brit, and For., fig. 128 ; 

 Hook. Syn. Fil., t. 2, fig. 13, a. b. 



Obs. — This is a very distinctly marked genus, readily 

 distinguished from Dirjisonia and its allies by the outer 

 valve being special, and formed on the reflexed margin 

 of the frond as in Dicksonia, but superficially seated on 

 the edge of the segments, rising from the outer base of the 

 receptacle, and conniving- with the interior special indu- 



