Burke: Azolla filiculoides vs. Azolla

	Azolla filiculoides	Azolla
	duckweed fern, large mosquito fern	mosquito-fern
Habit	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.

	Azolla filiculoides	Azolla
Habitat	Ponds, backwaters, slow-moving streams.
Distribution	Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Idaho and western Montana. [WildflowerSearch map] [BONAP county map]	[BONAP county map]
Origin	Native	Native
Conservation status	Not of concern	Not of concern
Sibling taxa	A. microphylla
Subordinate taxa		A. filiculoides, A. microphylla
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Azolla

duckweed fern, large mosquito fern

mosquito-fern

Habit

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.