FILTCES. 101 



GENUS XI.— YSTOPTERI S, Bernh. 



Fronds produced from the upper part of the caudex and its 

 branches, approximate or solitary, once or more times pinnate, not 

 scaly beneath. Stipes not articulated to the caudex, nor in any 

 portion of its length. Veins all free. Sori punctiform, round, attached 

 to the back of the ultimate veins. Indusium hooded, attached' 'below 

 the sorus, entire. 



Name from ki'otis (kustis) a bladder, and 7rrepts (jpteris) a fern, on account of the. 

 hooded indusium. 



SPECIES I.-CYSTOPTERIS FRAGILIS. Bernh. 



Plates 1864, 1865, 1866, 1867. 

 Polypodium fragile and P. regium, Linn. Spec. Plant. 1553. 



Caudex short, rather stout, dividing into numerous short branches 

 or crowns, clothed with the more or less approximate bases of former 

 fronds. Fronds several, close together at the apex of each branch 

 or crown of the caudex. Stipes from one-third as long as to as long as 

 the lamina, slender, very brittle, rarely stouter and tough, with sparse 

 pale linear-lanceolate scales at the base, and a few hair-like deciduous 

 ones in the upper part, but no glands. Lamina perishing in autumn, 

 or sub-evergreen, oblong-lanceolate or strapshaped-lanceolate, sub- 

 tripinnate or bipinnate, lowest pair of pinnse almost always smaller 

 than the succeeding pair, and never conspicuously larger ; pinnules 

 serrate or crenate or pinnatifid or pinnatipartite ; teeth of ultimate 

 segments usually entire, with the ultimate veins running in their 

 apices, or notched with the veins running into the notches ,• rachis 

 and lamina usually without glands. Indusium generally without 

 glands, rarely glandular. Spores muricated with numerous long 

 slender acute spine-like tubercles, or tuberculated with sparse large 

 blunt tubercles. 



Subspecies I.— Cystopteris eu-fragilis. 



Plates 1864, 1865. 



Babenh. Crypt. Vase. Europ. Exsicc. No. 14. 

 C. fragilis, Milde, Fil. Europ. p. 147. 



Caudex short, rather stout, not creeping, dividing into several short 

 branches or crowns, clothed with the more or less approximate bases 

 of former fronds. Fronds several, close together at the apex of each 



