POLYPODIUM. 



87 



Dictyopteris (Dic-ty-op'-ter-is), Presl. This small sub-genus belongs, 

 like the last, to the Desmobryoid series, in which the fronds are adherent 

 and continuous with the rhizome. The venation is similar to that of Sagenia 

 (Nephrodium), i.e., anastomosing (intermixing copiously). In some species, 

 the spore masses are biserial (disposed in two rows), e.g., in P. Barberi ; 

 while in others they are scattered irregularly, a character which is shown best 

 in P. sparsiflorum. 



Dipteris (Dip'-ter-is), Reinwardt. A small yet very interesting section 

 of the extensive sub-genus Phymatodes. It is of thoroughly distinct aspect 

 through the flabellate (fan-like) form of the fronds : these are divided into 

 two distinct halves, which are deeply lobed from the circumference in the 

 direction of the base. P. Dipteris is the typical representative of this 

 section. 



Drynaria (Dryn-a'-ri-a), Bory. In this small yet very distinct section 

 of the sub-genus Phymatodes, the barren and fertile fronds are sometimes 

 distinct, a character well illustrated by P. quercifolium ; when they are not 

 distinct, the base of the ordinary one is pinnatifid (divided half-way to the 

 midrib) like a stalkless Oak-leaf, brownish in colour, and rigid in texture, 

 as in P. Heracleum. 



Eupolypodium (Eu-pol-yp-od'-i-um), Linnceus. This is the most 

 extensive sub -genus belonging to the Eremobryoid series (composed of plants 

 with fronds articulated at the point of junction with the rhizome, and sj^ore 

 masses generally, but not always, terminal on the veins). The veins are free 

 and the spore masses are round, except in a few species in which they are 

 oblong, and which form the section Grammitis. The outlines of the fronds 

 and their divisions are numerous, some having entire (undivided) fronds, as 

 P. zeylanicum, while others have them pinnatifid (the lobes reaching half- 

 way or more down to the main stalk), such as those of P. khasyamim. The 

 majority of the species, however, have fronds distinctly pinnate (divided to 

 the midrib), with leaflets closely set, enlarged, and casually confluent at the 

 base, as is frequently seen in the typical P. vidgare ; some have their fronds 

 bipinnatifid or even bipinnate (twice divided nearly or quite to the midrib), 

 e.g., P. hymenophylloides, and a few are tri- or quadripinnatifid (three or 

 four times divided nearly to the midrib), a character shown to perfection in 

 P. millefolium. 



