Flora of North America species comparison

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Azolla filiculoides

duckweed fern, large mosquito fern, mosquito fern, Pacific mosquito fern, water fern
Habit Plants green to yellowish green or dark red, with 2 growth stages; plants fertile only in mature stage, generally in late spring.
Stems

prostrate when immature, 1–3 cm, internodes elongate to 5 mm, becoming nearly erect to 5 cm or more when mature and crowded.
Hairs

on upper leaf lobes strictly unicellular.
Megaspores

warty with raised angular bumps, each with a tangle of filaments.

Azolla filiculoides
Habitat Stagnant and slow-moving waters.
Distribution
from FNA
AZ; CA; OR; WA; BC; Mexico; Central America; Europe; ne Asia; s Africa; Pacific Islands in Hawaii
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Discussion

Azolla filiculoides is cold tolerant, surviving even in fragmented parts under thin ice. It usually reaches a climax population in late spring, becomes fertile, collapses, and is replaced by other more heat-tolerant aquatics such as Lemna spp. Hybrids between this species (male) and A. microphylla Kaulfuss (female), a species of Central America, South America, and the West Indies, have been reported (Do V. C. et al. 1989). V. M. Bates and E. T. Browne (1981) reported A. filiculoides from Georgia, far removed from its main range in western North America. The most likely explanation is that the plants represent escapes from horticulture.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 2, p. 341.
Parent taxa Azollaceae > Azolla
Sibling taxa
A. caroliniana, A. mexicana
Name authority Lamarck: in Lamarck et al., Encycl. 1: 343. (1783)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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