232 F I L I C E s. 



the veins very thick, sunken, and forked. Indusium coriaceous, reni- 

 form, about equal with the margin of the crenules. 



Plate 32. — Fig. 2. Portion of a plant, of the natural size. 2 a. 

 Dorsal view of a portion of a sterile frond, showing its venation. 

 2 b. Portion of a fertile frond, showing the sori, with and without the 

 indusium. 2 c. Scale from a rootstock. 2 d. Sporangium. — The 

 details more or less magnified. 



74. CYSTOPTERIS, Bernh., J. Sm., Hook. 



(Polypodii Spec. Linn. Aspidii Spec. Sw. & Auct. Cyathe^; Spec. Sm. 

 Athyrii Spec. Roth.) 



In habit the few species which Cystopteris contains claim a strong 

 affinity with Leucostegia and Microlepia of Presl and J. Smith. The 

 sori it is true, are seated on the back of a segment, but yet not farther 

 removed from the margin than we find them in Microlepia trichosticha 

 and some states of M. polypodioides. The indusium of Cystopteris is 

 inflated or cucullate, but laterally attached by a broad base, as in 

 Leucostegia. Hence our reason for placing it in the Davalliece section 

 of the Dicksoniew. 



1. Cystopteris Douglasii, Hook. 



Cystopteris Douglasii, Hook. Spec. Fil. 1, p. 200. 



Hab. Sandwich Islands : on mountains, at the elevation of 4,000 

 feet. 



Plant with a short and globose rootstock, covered with long brown 

 hairs and slender paleae. Stipe naked, from one to 3 inches long, 

 slender, compressed, smooth, furnished with narrow and membrana- 

 ceous chaffy scales at the base. Fronds generally about equal in 

 length with the stipe, oblong-lanceolate, pinnate at the base, towards 

 the point pinnatifid. Inferior pinnae broadly-ovate, obtuse, pinnatifid j 



