Azolla filiculoides
duckweed fern, large mosquito fern
Specimens
Photos

Distribution: Occurring on both sides of the Cascades in Washington; British Columbia to California, east to Idaho and western Montana.

Habitat: Ponds, backwaters, slow-moving streams.

Origin: Native

Conservation Status: Not of concern

Description:
General:

Floating aquatic perennials, green to yellow-green to dark red, with 2 growth stages and only fertile in mature stage; stems prostrate and 1-3 cm when immature, nearly erect and 3-5 cm at maturity when crowded, lacking hairs; roots 3-5 cm.

Leaves:

Leaves sessile, and alternate, overlapping, 0.6-2 mm broad, 2-lobed, with 1-celled hairs on adaxial surface of upper lobe; emersed lobe greenish to reddish with narrow colorless margin, immersed lobe slightly larger than emersed lobe and often lacking color.

Spores:

Sporocarps in pairs at base of lateral branches, megasporocarps each containing 1 megasporangium that produces 1 spheric megaspore 0.2-0.6 mm with a warty surface and tangled filaments; microsporocarps globose, apex with a rounded protuberance, 10-27 micrometers in diameter, containing up to 130 microsporangia, microsporangia each containing 32 or 64 microspores 3 micrometers in diameter.

Accepted Name:
Azolla filiculoides Lam.
Publication: Encycl. 1: 343. 1783.

Synonyms & Misapplications:
(none provided)
Additional Resources:

PNW Herbaria: Specimen records of Azolla filiculoides in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Azolla filiculoides checklist entry.

E-Flora BC: Azolla filiculoides atlas page.

CalPhotos: Azolla filiculoides photos.

USDA Plants: Azolla filiculoides information.

16 photographs:
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