Polypodium.] XCIV. FILICES, 559 
sori even when young. For the Table of Species, see the Generic 
Table above, p. 554, n. 18. 
1. P. vulgare, Linn. (fig. 1281). Common P.—Rootstock thick, 
woody, and creeping. Fronds about 6 inches to a foot high, of a firm 
consistence, without any scales on their stalk, broadly oblong-lanceolate 
or somewhat ovate in their general outline, simply pinnate or deeply 
pinnatifid ; the linear-oblong segments adhering to the main stalk and 
usually connected with each other by their broad bases. Sori rather 
large, of a golden yellow, in two rows along the under side of the 
upper segment. When bearing fruit these segments are usually entire 
or nearly so, and obtuse; when barren they are often slightly toothed ; 
and monstrous states not unfrequently occur with the segments 
variously lobed or branched. © 
In sheltered places, on trunks of old trees, walls, moist rocks, and — 
shady banks, throughout Europe and temperate Asia, from the Mediter- 
ranean to the Arctic regions, and in North America and South Africa. 
Common in Britain. Fr. summer and autumn. [P. cambricum, Willd. 
is a Welsh form with pinnatifid segments. ] | 
2. P. Phegopteris, Linn. (fig. 1282). Beech #ern.—Rootstock creep- 
ing. Fronds rather slender, 6 inches to a foot high or rather more, 
including their long stalks, broadly ovate-lanceolate and acuminate in 
their general outline, once pinnate; the segments deeply pinnatifid, 
narrow-lanceolate, gradually diminishing from the base to the end of 
the frond, and all, except sometimes the lowest pair, adhering to the 
main stem. by their broad base. The midrib, principal veins, and 
margins of the frond more or less hairy on the under side, by which 
this species may be readily distinguished from the smaller specimens 
of Aspidium Thelypteris, which it sometimes resembles. Sori rather 
small, near the margins of the lobes. Phegopteris polypodioides, Fée. 
_ In moist situations, in hilly districts, in Europe and Western Asia, 
_ from the Pyrenees and Alps to the Arctic regions, and in North America. 
In Britain, in western and northern England, Scotland, and Ireland. 
Fr. summer and autumn. 
3. P. alpestre, Hoppe. (fig. 1283). Alpine P.—Stock short, often 
forming severalcrowns. Fronds tufted, 1 to 3 feet high, twice pinnate ; 
the segments numerous, oblong or lanceolate, deeply pinnatifid, and 
sharply toothed, the larger ones usually about half an inch long. Sori 
circular, without any indusium whatever; this character alone dis- 
tinguishes this plant from the smaller states of AsPenium Filix-feemina 
and from some forms of Aspidium spinulosum, which it closely resembles 
in all other respects. Athyriwm alpestre, Milde. 
In the mountains of Europe and western Asia, from the Alps.and the 
Caucasus to the Arctic regions. In Britain, only in the Highlands of 
Scotland. Fr. summer. [P. flexile, Moore, is a variety found in the 
Forfarshire mountains, with very short stalks and segments. ] 
- 4. P. Dryopteris, Linn. (fig. 1284). Oak Fern.—Rootstock creep- 
ing, rather slender. Fronds slender but erect, on long stalks, broadly 
triangular or rhomboidal in their general outline, the leafy part 4 to 6 
inches long and at least as broad, twice pinnate, or rather, in the first 
instance, ternate; the lower pair of branches or pinnas on slender 
stalks, each often as large and as much divided as the rest of the frond ; 
the others much smaller and less divided, the terminal ones reduced to 
