
CYSTOPTERIS 137 
ROTUNDATUM (Fig. 134.)—Found by Мг. Clift ; pinnae round and 
very small at base, fronds narrow, with occasional elongated pinne. 
A similar form,.but with more even pinne for entire length, was 
found by the writer near Aberfeldy. | 
SERRATUM (Fig. 135).—Found by Mr. С. В. Wollaston and others ; 
a very fine form, with close-set, curved, and saw-toothed рїппг. 
S. Атвкү No. r.—The parent of plumosum Airey ; a markedly 
serrate form, but not tripinnate. 
SERRULATUM (Fig. 136).—A prettily saw-toothed dwarf form. 
STRICTUM (Fig. 137.)—This has been repeatedly found, and is 
distinguished by saw-toothed side divisions, which are usually 
extra short near the base, and occasionally 
somewhat irregular in length; not so robust 
as the normal. 
SUBSERRATUM (Fig. 138 and Plate XIT).— 
Found near Castle Howard by Mr. Monkman 
and near Todmorden by Mr. Stansfield ; 
in this: the pinne аге prettily blunt-toothed, 
especially on the lower side, the upper being 
often smooth. 
TRINERVIO-CORONANS.—Seemultifurcatum. 
TRINERVIUM.—Found in Wicklow by Dr. 
Kinahan and subsequently in considerable 
numbers in the Mourne mountains by Mr. 
W. H. Phillips; the two lowest pinne are 
considerably elongated. 
T. Hopcson#.—Found on Kirkley Moor 
by Mr. Hodgson ; the two lower pinna are 
developed into secondary fronds, so as to 
form a trident ; extremely distinct. 

Fig. 138. 
В. 5. subserralum. 
CYSTOPTERIS ЕКАСП 15 (THE BRITTLE BLADDER FERN) 
(Plate XIII) 
The Bladder Ferns (Fig. 139) derive their names, both popular 
and botanical, which are synonymous, from the fact that their 

Fig. 139. Cystopteris fragilis (pinnae). 
small round spore heaps are covered by thin, domed skins, looking 
like little bladders, while the term brittle is well applied, since the 

