104 



THE FLORIST. 



in Dryndria coronans, where, however, the sori are at other times, and 

 most frequently, normally punctiform. This latter abnormal condition 

 approaches very near to the normal condition of Selhyuea among the 

 Ggmnogrammece. These are exceptional instances which cannot readily 

 be reduced to rule, but fortunately they are few in number. 



The entire group comprises three subdivisions, marked out in the 

 first instance by the absence or presence of an indusium or cover to the 

 sorus, and next, by the position of this cover when it is present. Even 

 when there is no indusium, however, the sorus is not always exposed, 

 for in some few instances the margin of the frond is turned over in the 

 manner which, it has already been explained, is described by the term 

 spuriously-indusiate, so as to hide the spore-cases ; the latter, however, 

 are usually exposed. The subdvisions resulting from these characters 

 are as follow : — 

 Sori punctiform, &c. 



(a). Sori naked or spuriously-indusiate . . • §18. Polypodies. 



(b). Sori indusiate, i. e., with superior indusia . . ,\ (see forward). 



(c). Sori involucrate, i. e., with inferior indusia . • i 



The Polypodiece comprise sixteen genera, most of which are familiar to 

 cultivators, dot-like naked sori being their characteristic mark. The first 



group of genera, com- 

 prising those with spu- 

 riously-indusiate sori, 

 consists of : — Allosorus 

 (already mentioned to 

 have a close relation ■> 

 ship to Cryptogramma 

 among the Platylomece), 

 Struthiopteris, and 



Jamesonia. The "other 

 group comprises the 

 genera with plane fronds 

 not indusioid at the 

 margins, and consists 

 of: — Nothochlcena and 

 j Polypodium with free 

 veins ; Goniopteris with 

 the veins connivent ; 

 and Dictyopteris, Phle- 

 bodium, Goniop/ikbium, Campy loneur urn, Niphobolus, Pleopeltis, Dry- 

 naria, Aglaomorpha, Dipteris, and Lecanopteris, having the veins 

 variously reticulated. 



The group (b) with indusiate sori, are further divided by peculiarities 

 of the indusium in the manner following : — 

 Sori indusiate — 



Indusium reniform or peltate, attached by the sinus or 



centre, free at the margins . . . . . ^19. Aspidiece. 



Indusium rotundate or ovate, cucullate, attached trans- 

 versely by its base, free at the margin . . . . §20. Cystopleridece. 

 Indusium roundish or oblong, adherent at the base and 



margin, opening in front, i. e., exteriorly . . . §21. Davalliece. 



§18. Polypodies : Goniophlebium neriifolium. 



