48 
FERNS. 
[Asplenium. 
pinnule magnified. C, the same cut transversely. D, lower epidermis. E, trans- 
verse section of the leaf-s talk. F , indusium. G, theca and spores. H, young plant. 
Sort linear at first, afterwards oblong ; indusium linear, attached to a trans- 
verse vein, and opening on the opposite part of the sorus towards the central 
nerve of the pinna. This is a well-marked and extensive genus, of which Sprengel 
enumerates no less than 151 species ; of these ten only are British, which are very 
little or not at all altered by culture, they are therefore less liable to run into 
varieties than some other genera. It is only when the sori are in a young state 
that many species can be known to belong to this genus, as the indusia are so 
delicate that they are soon lost among the sori, which in many of the smaller 
species at last appear like round or oblong spots. 
1 . — ASPLENIUM SEPTENTRIONALE . 
FORKED SPLEENWORT. 
(Plate IV, tig. 1.) 
Cha. — Leaf linear, simple, bi- or tri-partite. Segments linear, 
sharply toothed at their extremity. 
Syn. — Asplenium septentrionale, Swz., Willd., Hull, Hojfm., Hook., Smith, 
Galp., Gray. — Acrostichum septentrionale, Linn., Bolt., Dicks., Ehrh., 
With., Huds., Lightf. — Scolopendrium septentrionale, Roth. — Amesium 
septentrionale, Newm. 1854. 
Fig. — E. B. 1017 .—Flo. Dan. 60 .—Bolt. 8 .—Flo. Lon. 102.— Ger. 1561 — 
Newm.p. 205 (1854). 
Des. — Leaves very numerous, upright when young, drooping 
afterwards, rigid, 1 to 3 inches high, simple or cleft near the top 
into two or three linear sharp-pointed alternate segments, which in 
proportion to their size are furnished at or near their extremity with 
from one to three acute, but not spinous teeth. Sori one on each 
side of the segment, nearly longitudinal, concealed at first by a white 
indusium, attached at the outer edge ; afterwards the swelling sori 
throw back the indusia, covering the whole of the segment, and 
finally curving and contorting it in a curious manner. 
Mr. H. C. Watson writes thus: “Although quite a northern Fern, I observed 
the young fronds destroyed by a frost of 25 degrees Fahr., in April 1835. The 
plant had been under a glass in a cold frame during winter, where the tem- 
perature inside had risen a few degrees higher than outside by day, and had 
never been allowed to sink to the freezing point at night, in consequence of a 
thick covering of mats.” 
Sit. — On the rocky clefts of mountains, chiefly in the north. Not in Ireland. 
Hab. — Eng.: In situations probably exceeding 1000 feet in height in Cum- 
berland, where it occurs sparingly on rocks, between the vale of Newlands and 
Borrowdale. — Walks: Craig Dliw (a mile above Llanberris Church), Cacrn., Mr. 
C. C. Babington. Snowdon (rare), Mr. J. E. Bowman. Llvn-y-cwm, N. Wales, 
Mr. W. Wilson. — Scot. : Arthur’s Seat, Edinburgh (above the railroad), Jedburgh, 
&c., Mr. II. C. Watson. Blackford Hill, Ellin., Mr. W. Brand. 
Geo. — Holland, Switzerland. Not unfrequent throughout Europe. 
