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


SALVINIACEAE
SALVINIA FAMILY

DUCKWEED FERN

Azolla filiculoides Lam. (Fig. 48)

Small floating aquatic plants 1/4 to 1 inch long which branch pinnately and bear crowded overlapping 2-lobed leaves on the upper side of the stems, a few roots on the lower side. Spores are contained within a special structure called a SPOROCARP, submerged in water on lower side of the stem. Two or more sporocarps may occur on one branch, each containing 1 megaspore or microspores.

Sometimes called the Fern-like Azolla, these moss-like plants are green or dark red, often occurring in masses that cover ponds or pools of quiet water. Widely scattered among the western states, in lower elevations in California in the Sierras at such places as Three Rivers, La Grange, Mormon Bar near Mariposa, north to Modoc. The species also occurs in Mexico and South America.

Fig. 48 DUCKWEED FERN (Azolla filiculoides)
[click to enlarge]

Fig. 48 DUCKWEED FERN (Azolla filiculoides). Upper: This small fern can be found floating in sluggish streams of foothills. Lower left: Top view (left) of one branched plant and bottom view (right) showing two sporangia and microspores. Lower right: Close view of a mass of this fern in its normal habitat.



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