General Information

COMMON NAMES: Azolla Water-fern, Pacific Azolla , Red Water-fern, Water Moss, Water Velvet, Fairy Moss, Mosquito Fern, Duckweed Fern GLOBAL DISTRIBUTION: NATIVE N.America - S.America COOK ISLANDS STATUS: Introduced - Recent (1980s), Naturalised; S.Group - widespread and common; Freshwater, wetlands - ponds SIGNIFICANCE LIST: Manure, Cover; weed - moderate, Invasive - mild KEY FEATURES: Small floating fern, forming mats. Each plant is an oval frond to 3cm, consisting of a stem with dangling roots and alternate leaves, and, at intervals, detachable side branches. LEAVES overlapping, small, to 3mm, 2-lobes; LOWER LOBE boat-like and floating; UPPER LOBE green, tinged red under stress; aerial with a cavity full of nitrogen-fixing cyanobacteria (=bluegreen algae). SIMILAR SPECIES: Azolla pinnata R. Br. (NATIVE: Africa - PNG/Australia; n. to Japan; EXOTIC Marjuro (rare 2003), NZ).

Cook Islands Distribution

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Southern Group: Present    Makatea: Present
RR	MG	AT	MK	MT	AK	PL	TK	MN
P	++++	++	P	P		-	-	-

Northern Group: -
TN	MH	RK	PK	NS	SW
-	-	-	-	-	-

Azolla filiculoides Lam., 1783
SYNONYMS: Azolla filiculoides var. rubra (R.Br.) Strasb.; Azolla microphylla Kaulf., 1824; Azolla caroliniana Willd., 1810

TAXONOMY: PLANTAE; PTERIDOPHYTA (=Pterophyta); Salviniales; AZOLLACEAE

SIGNIFICANCE NOTES -
POSITIVE SIGNIFICANCE: Manure, Cover. Comments: Shades out weeds in Taro patches and is a green manure.
NEGATIVE SIGNIFICANCE: weed - moderate, Invasive - mild

IDENTIFICATION: Small mat-forming floating fern. Each plant is an oval frond to 3cm; each frond is a stem (=rhizome) with roots at intervals, alternate leaves, and secondary branches which can detach as separate plants. LEAVES overlapping, minute, to 3mm, 2-lobed; LOWER LOBE colourless, boat-shaped, floating on the water; UPPER LOBE green tinged red when stressed, thick, aerial, central cavity housing nitrogen-fixing cyanobacteria (=blue-green algae) named Anabaena azollae, each being a microscopic unbranched filament of cells.

Vouchers:
None Recorded.

References:
p.28 Neal - In Gardens of Hawaii
p.132 Hortus 3rd
p.122 Royal Hort. Soc. Index of Garden Plants
p.448 Tropica

Data Update History (information):
zTX, zB02, zM03b, zD02

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