Aspidium. | XCLV. FILICES. 559 
so that, when raised all round by the growth of the spore-cases, it becomes 
either peltate or kidney-shaped. 
A very large genus, ranging over every part of the globe, only distin- 
guished from Polypodiwm by the indusium. . In modern British Fern-books 
it is usually divided into two, Lastrea and Polystichum, according to 
whether the attachment of the indusium is central or towards the margin, 
a minute character, unconnected with habit, often difficult to appreciate, 
and sometimes inconstant. The Table of species will be found under the 
Generic Table above, p. 554, n. 13. 
1. 4. Lonchitis, Sw. (fig. 1282). Holly Shieldfern, Holly Fern.— 
Stock short and thick. Fronds tufted, usually 6 inches to a foot high or 
rather more, stiff, linear-lanceolate in their general outline, simply pinnate, 
leafy from the base, the common stalk very scaly below. Segments mostly 
broadly lanceolate or almost ovate, curved, prickly-toothed, enlarged at the 
base on the inner or upper side into a toothed angle or lobe, all nearly 
sessile, but attached by the midrib only, stiff, glabrous above, with a few 
scaly hairs underneath ; the central ones about an inch long; the lower 
ones smaller and broader, often ovate. Sori circular, rather large, with a 
not very conspicuous peltate indusium in the centre. Polystichum Lon- 
chitis, Roth. 
In the clefts of rocks, in all the great mountain regions of Europe and 
central and Russian Asia, from Spain ‘and Italy to the Arctic regions, and 
in North America. In Britain, only in the mountains of Scotland, northern 
England, North Wales, and Ireland. #7, summer and autumn. 
2. A. aculeatum, Sw. (fig. 1283). Prickly WShieldfern.—Fronds 
tufted, arising from a short thick stock, 1 to 2 feet or rather more high, 
stiff, twice pinnate, broadly lanceolate in outline, with the lower pinnas 
decreasing in length; the stalk below the leafy part 1 to 6 inches long, 
very shaggy with brown, scarious scales. Primary branches or pinnas 
shaped like the whole frond of 4. Lonchitis in miniature, being pinnate, 
with their segments shortly ovate-lanceolate, curved and prickly-toothed, 
with a prominent angle or lobe on the inner or upper side; the lower ones, 
or sometimes nearly all, attached by their midrib, the upper ones decurrent 
on the stalk or united at the base. Sori rather small, with a central but 
not. very conspicuous indusium. A. lobatum, Sm. Polystichum acu- 
leatum, Roth. 
On hedge-banks and in shady places, in temperate and southern Europe, 
from the Mediterranean to Scandinavia, extending eastward into central 
Asia; in North and South America, and generally in the southern hemi- 
sphere. Frequent in Britain. fr. summer and autumn. A. angulare, 
Willd., is a rather larger, more luxuriant, and less stiff variety, usually 
more divided, with more distinct segments, the lower ones evidently 
stalked. 
3. A. Thelypteris, Sw. (fig. 1284). Marsh Shieldfern, Marsh Fern. 
—Rootstock creeping, with single, not tufted, erect fronds as in Polypo- 
dium Phegopteris, to which this fern bears considerable resemblance. It 
is taller, usually 1 to 2 feet high, quite glabrous, with a rather slender but 
stiff stalk, without scarious scales. The leafy part lanceolate, pinnate, 
with deeply pinnatifid pinnas, which are not crowded, and the lowest rather 
distant and smaller ; all attached to the central stalk by their midrib or 
