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ed. iii., p. 88 . — M o o r e , Nat. Pr. Brit. Ferns, t. xlvi., A .—
M e t t e n iu s , P'il. Hort. Lips., p. 97. — L aw s o n , in Canad. Naturalist,
¡., p . 286. — H o o k e r & B a k e r , Syn. Fil., p. 10 3 .—
M i ld e , Fil. Eur. et Atl., p. 147. — W i l l iam s o n , Ferns of Kentucky,
p. 103, t. xxxviii. — D a v e n p o r t , Catal., p. 33.
dium fra g ile , L in n æ u s , Sp. PL, p. 1553.
Aspidium fra g ile , S w a r t z , Syn. Fil., p. 58. — S c h k u h r , Krypt. Gew.,
P- 5 3 > 5 4 - 5 5 - 56. — W il ld en o w , Sp. Pl., p. 280.
Cyathea fr a g ilis . S m it h , “ E n g l . Bot., t. 1 5 8 7 . ”
Cystea fr a g ilis . S m ith , “ Engl. Flora, iv., 285.”
Cystopteris tenuis, D e s v a u x , “ Prodr., p. 263.”—S ch o t t, Gen. Fil.— M oo r e ,
Index Fil., p. 285.
Nephrodium tenue, M ic h a u x , E l. A m . - B o r . , ii., p . 269 .
Aspidium tenue, S w a r t z , Syn. Fil., p. 58. — S c h k u h r , Krypt. Cew.,
p. 196, t, 53, b. — W i l ld e n o w , Sp. Pl., v., p. 279. — P u r s h ,
FI. Am. Sept., ii., p. 665.
Cystopteris Douglasii, H o o k e r , Sp. Fil., i., p. 2 0 0 ; Ic. PL, t. 9 5 5 .
Cystopteris Sandvicefisis, B r a c k e n r id g e , Fil. U. S. Ex. Expcd., p. 23 4 .'
H a b . — In crevices of shaded rocks and among stones, less commonly
at the base of trees, or in earth along rivulets ; from Arctic
America to Tierra del Fuego, and from Iceland to New Zealand, one
of the most universally distributed of ferns.
D e s c r i p t i o n : — The root-stock of this fern sometimes
attains a length of four or five inches, but is usually shorter
and more condensed. While it is really quite slender, it is
‘ F or much other synonymy see the -writings above referred to, especially those of
Hooker, Moore and Milde. Many nominal species o f Cystopteris are now commonly
referred to this one ; and Milde even goes so far as to unite with it C. alp ina (or regia) ,
which most authors have considered fairlv distinct.
made to appear rather stout by the fleshy bases of the stalks,
which remain attached to it a long time. Mr. Moore considered
the North American plant with a “ wide-creeping rhizome
" distinct from the European, and calls it C. tenuis, but
admits that some of the North American specimens are true
C. fragilis. I find as great a difference in the root-stocks of
European as of American plants, and so far from recognizing
two species, I can find no varieties sufficiently distinct to be
worth careful definition. The scales, which are found at the
apex of the root-stock, are thin and delicate, and usually entire
and slender pointed ; but in the plant selected for Mr.
Faxon’s pencil they are accompanied by slender moniliform
filaments, and often terminate in a rounded gland.
The fronds grow in a dense cluster, and are supported
on slender and brittle stalks commonly from four to six
inches long. The bases of the stalks are enlarged and of
a dark color, while the rest of the stalk is green like the
fronds. The fronds are only three and a half inches long in
some little specimens recently brought from Disko Island ; but
commonly the length is six or eight inches and the breadth
about half as much. In the southern part of Mexico, in the
Hawaiian Islands, and in the Canaries, fronds are found over
a foot long. The general shape of the fronds is ovate-lanceolate,
commonly a little narrower at the base than at the
second or third pair of pinnæ. The pinnæ have a narrowly
winged midrib, so that while the frond appears bipinnate, it
is really but once pinnate, and has pinnatisect pinnæ.
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