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Ferns of the Sierra (1960) by Robert J. Rodin


WOODSIA

Small dark-green ferns, bearing sori the whole length of the fronds. Round sori in a submarginal position borne on backs of free veins with a delicate cup-like indusium attached under the sporangia. The indusium partly or entirely encloses the sporangia at first, often dividing early into irregular lobes, forming a fringe around the sporangia.

KEY TO THE SPECIES:

Fronds with short hairs, glandular, divisions of the indusium narrow W. scopulina
Fronds without hairs or glands, indusium fringed with hairs W. oregana

Fig. 44 ROCKY MOUNTAIN WOODSIA (Woodsia scopulina)
[click to enlarge]

Fig. 44 Above: ROCKY MOUNTAIN WOODSIA (Woodsia scopulina). Grows in a cool canyon in moist soil.

Fig. 45 ROCKY MOUNTAIN WOODSIA (Woodsia scopulina)
[click to enlarge]

Fig. 45 Right: ROCKY MOUNTAIN WOODSIA (Woodsia scopulina). Upper left: Lower side of a frond with its circular sub-marginal sori. Upper right: Top of one frond covered with short hairs. Lower left: Cup-like indusium attached beneath the sporangia of this species. Lower right: One fringed indusium beneath the sporangia from OREGON WOODSIA (Woodsia oregana).

ROCKY MOUNTAIN WOODSIA

Woodsia scopulina D. C. Eat. (Fig. 44, 45)

Clusters of fronds 5 to 10 inches high with lower part of stalk dark brown, having a few scales. Dark green fronds broadly lancelate, covered with scattered multi-cellular or glandular hairs, usually bi-pinnate, or pinnate with segments deeply cut and toothed. Sori submarginal, indusium delicate, cup-like, divided into narrow divisions, ending in hairs (Fig. 45).

This fern closely resembles Cystopteris fragilis in size and general appearance. Both grow in moist places along streams. In Woodsia fronds are darker green, slightly curled down around the margins and sporangia are green when young, light brown when mature and after spores are shed. Young sporangia in Cystopteris are black; older sporangia appear brown after their spores are shed.

Although this fern is found in the Rocky Mountains, as its common name implies, and is widely distributed as far north as Alaska, south to Tennessee, Oklahoma and North Carolina, and around the Great Lakes, it is only known from a few places in the Sierra Nevada at elevations from 4,000 to 9,000 feet including Ouzel Basin and Hamilton Lake area in Sequoia National Park and from Mono Pass and the Ledge Trail in Yosemite. It has been found as far north in the Sierra as the Modoc Lava Beds.

OREGON WOODSIA

Woodsia oregana D. C. Eat. (Fig. 45, 46)

Very similar to Rocky Mountain Woodsia in general size and shape

Fig. 46 OREGON WOODSIA (Woodsia oregana)
[click to enlarge]

Fig. 46 OREGON WOODSIA (Woodsia oregana). One frond showing the sori in submarginal positions.

of fronds and location of sori. Here fronds are glabrous, free from any glands or pubescence. The indusium seated under the sporangium has hair-like lobes, which in young sporangia reflex upward, and appear to enclose the sporangia (Fig. 45).

Found from 4,000 to 5,000 feet elevation at a few places from San Bernardino County northward into Washington. Not common in the Sierra. This species closely resembles Cistopteris as noted in the above species. It is found from Lower California to British Columbia, in Quebec, Oklahoma, and New Mexico.



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