Aspidium.] 
FERNS. 
35 
9. — ASPIDIUM DILATATUM. 
GREAT SHIELD FERN. DILATED SHIELD FERN. 
(Plate 2, fig. 12, 13.) 
Cha. — Frond tripinnate, triangular. Pinnae opposite, lobes 
deeply dentate, spinulose, petioled. Rachis scaly. 
Syn. — Aspidium dilatatum, Willcl., Spreng., Forst., Galp., Gray.-~- Aspidiuni 
spinulosum, Swz.. Sibth., Hook, (not a.). Mack., Schk. — Poly po dium 
cristatum, With., Bolt., Huds., Ehrh., Moench., Light f . — Polypodium 
dilatatum, Hoffm., Mull. — Polystichuin multillorurn, Roth. 
Fig. — E. B. 1461 .—Bolt. 23.— Schk. fil. 47. 
Des. — Root black, tufted. Frond tripinnate, triangular, from a 
few inches to two feet .high, dark green, and drooping. Pinnae 
opposite, smooth, oblong, obtuse, pinnate, except the lower pair 
which are doubly pinnate. Lobes ovate, pointed, convex, deeply 
but irregularly serrated and spinulose, petioled, their midribs straight. 
Rachis covered with broad, brown scales. Sori all the summer, 
distinct. Indusiums soon becoming obliterated, round, with a 
lateral notch. 
A very variable plant, altered much by cultivation and circumstances, thus 
if it grow in a situation which is wet in the spring and dried up in the summer, 
as on the margin of a pond, it will become var. (i, very dark, large, and quite 
drooping. Continued wet will elongate the frond and separate the pinnee and 
lobes as in var. y. A young plant is only twice pinnate and flat. A dry and rocky, 
or a confined situation will render the frond small and less divided, the lobes 
blunt, deflexed, and drooping : thus starved it becomes the Aspidium duineto- 
rum of Smith (var. £)• I know not the nature of the habitats in which 
the reflexed var. (e) of Bree grows, and can only regret that Botanists do 
not record the circumstances, as well as the places, in which plants are 
found. The varieties reflexum and dumetorum are, I believe, not altered by 
cultivation, and Sir J. E. Smith implies in his description of the latter, that 
its spores produce the same variety. 
a ( dilatatum ) Frond sub -tripinnate, triangular, ovate. Pinnules petioled. 
(I ( ) Frond tripinnate, deflexed, triangular. Pinnules convex. 
y ( ) Frond tripinnate, triangular, elongated. Pinnules some- 
what decurrent, and distant from each other. 
5 (Dumetorum ) Frond small, triangular, drooping. Pinnules blunt. 
e (m/leaum, Bree.) Frond small. Pinnules concave, and dark green. 
Sit. & Hab. — -a (b y. Very common in damp hedge-rows and swampy 
woods, ascending to an elevation of 1000 yards in many parts of the High- 
lands, and probably even to 1200 yards on the Caimgoram range . — K : Der- 
byshire (rare), Mr. J. E. Bowman and Dr. Howitt. Common about Settle, 
Yorks., Mr. J. Tatham. Powcrscourt Waterfall, and side of Djouce Moun- 
tain, Ireland (abundant), Mr. Mackay. Black Rock, Cromford, Derb., G. F. 
t. : Plentiful about Penzance, Cornwall, Rev. W. Bree. Ben-na-Baird, 
Aberdeensh., Mr. H. C. Watson. 
Geo. — Common throughout Europe, and from Pennsylvania to Virginia. 
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