106 



THE FLORIST. 



lepia, with intramarginal sori ; Dacallia and Loxoscaphe with marginal 

 sori ; and Prosaptca, a curious genus, in which the sorus is set in a 



§21. Davallte.e : Davallia bullata. 



short marginal cavity, formed by the junction of a thick coriaceous 

 indusium with the substance of the frond, the two being nearly alike in 

 texture. 



The group (e), with involucrate sori, need some explanation. The 

 sorus is here set within a round or two-valved indusium, which is 

 called an involucre from being placed beneath the sorus. There are 

 two sections ; in one the margin of the frond and the special indusium 

 coalesce to form an entire or two-valved cup, and hence the cup is 

 marginal ; in the other the cup is a distinct body entirely within the 

 margin, and formed of the indusioid substance. Thus we are enabled to 

 separate the following groups : — 



Sori involucrate — 



— in a marginal entire or two-valved cup . . . §22. DicTcsoniem. 



— in a dorsal entire-lobed or fringed cup , . . §23. Peranemece. 



The Dicksoniece, the 

 peculiar structure of 

 which has just been 

 briefly explained, com- 

 prise the following 

 genera : — Dicksonia, 

 Diclisodon, Cibotium, 

 and ? Pcesia, with 

 distinctly two-valved 

 indusia ; Dennstcedtia, 

 with cup-shaped de- 

 flexed indusia ; and 

 Deparia and Cioni- 

 dium, with cup-shaped 

 extrorse- marginal in- 

 dusia. Pcesia, which 

 long remained un- 



\ 23. Pbrankme.e : (a) Woodsia ilvensis ; (A) Woodsia obtusa ; 

 (c) Woodsia mollis. 



