The most important of the larger species are woodwardia, aspidium, asplenium, and, above all, the common pteris.

Woodwardia radicans is a superb, broad-shouldered fern five to eight feet high, growing in vase-shaped clumps where tile ground is nearly level and on some of the benches of the north wall of the Valley where it is watered by a broad trickling stream.

It thatches the sloping rocks, frond overlapping frond like roof shingles.

The broad-fronded, hardy Pteris aquilina, the commonest of ferns, covers large areas on the floor of the Valley.

No other fern does so much for the color glory of autumn, with its browns and reds and yellows, even after lying dead beneath the snow all winter.