Gymnogramme .] cvni. polypodiaceje. 
579 
11. Blechnum. Sori linear, parallel on each side of the midrib, distant 
from the margin. 
B. Capsules opening irregularly, placed on a receptacle at the margin of the 
frond and terminating a vein ; their ring transverse. 
13. Trichomanes. Sori marginal. Involucre monophyllous, subcylin- 
drical. Receptacle filiform. 
14. Hymenophyli.um. Sori marginal. Involucre 2-valved. Recep- 
tacle subclavate. 
A. Capsules opening transversely, placed on the hack of the frond 
but sometimes close to its margin ; their ring vertical, usually 
incomplete. Cellular tissue of the frond compact. 1 Poly- 
poDtEiE. (Gen. 1 — 12.) 
1. Ckteeach Willd. Ceterach. (Tab. IX. f. 1.) 
Sori oblong or linear straight, scattered, arising from reticu- 
late veins, covered (as is the whole back of the frond) with 
chaffy scales. Involucre none (or obsolete). — Name: from the 
Celtic cedor wracli, double rake ; or perhaps from chetherak, 
a similar plant employed by the Arabian and Persian physicians 
for obstructions in the viscera. 
1. C. offeindrum Willd. (common C., or Scale-fern ') ; fronds 
pinnatifid covered beneath with imbricate chaffy scales, seg- 
ments ovate obtuse, scales entire. Newm. p. 293. 2 Grammitis 
Ceterach Sw. Scolopendrium Sm. : E. B. t. 1244. Asple- 
nium L. Notolepeum Newm. ed. 3, p. 277. 
Rocks and old walls, chiefly in limestone districts in England 
and Ireland. Rare in Scotland ; near Perth ; Paisley ; Glasgow ; 
walls about Drumlanrig, Dumfriesshire ; Kilfinnan, Argyleshire. 
If.- 4 — 10. — Mr. IV. Wilson finds traces of an involucre on the lower 
side of the sorus, viz. “a narrow membrane, fringed with the same 
chaffy scales which cover the back of the frond : ” see also Bauer and 
Hooker’s Genera of Ferns, t. 113, a. 
2. Gymnogramme Desv. Gymnogram. 
Sori oblong or linear on forked free veins, not covered with 
scales. Involucre none. — Name: from yvpvoc, naked , and 
ypappi], a line. 
1 The compactness of the tissue arises not only from the small size of the cel- 
lules, but also from there being several in the thickness of the frond, giving it a 
certain degree of opacity: in the next group (B.), the cellular tissue is lax and 
almost transparent, from the larger size of the cellules, and their being often only 
one in the thickness of the frond, in this respect resembling the leaves of most 
Mosses , but differing from them by having the nerves and veins composed of that 
kind of vascular tissue called ducts. 
2 We shall refer to the figures in Newman’s History of British Ferns, edition 
second, by merely quoting the page; and to the third edition by the addition of 
ed. 3. When the name only is referred to, we shall merely indicate the authority 
by Newm. 
C C 2 
