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NZ Plants

Azolla rubra - Pacific azolla, karerarera, retoreto

Aquatic ferns, family: Salviniaceae

  • Floating plant from above

    L Jensen

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  • Frond upper surface, leaflets with green dorsal lobes

    L Jensen

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  • Frond lower surface, leaflets with pale ventral lobes

    L Jensen

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  • Frond midrib (rachis) side view, leaflets with large dorsal lobes (green) and smaller ventral lobes (pale)

    L Jensen

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  • Detached leaflet with dorsal lobe (above) and ventral lobe (below)

    L Jensen

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  • Rachis with large male sporocarp and a small female sporocarp (red) to the left

    F Carrapico

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These free-floating ferns have a symbiotic relationship with colonies of the cyanobacterium, Anabaena azollae, located in pouches in their leaves. 
The bacterium obtains organic compounds from the fern and converts atmospheric nitrogen into organic compounds that are utilised by the fern. 

Vegetative characteristics

Fertile frond and sporangia

Plant form: Horizontal floating stems with leaves up to 2 mm in length

Frond appearance: Similar to sterile frond

Frond stalk, midrib: branching irregularly

Sporangium location: inside a capsule (sporocarp)

Frond shape:  triangular

Sporocarp position: on ventral (lower) leaflet lobe

Frond blade:  

Sporangia distribution:

Frond surface: epidermal cells with projections

Sporocarp shape: rounded with a stalk

Leaflets: dorsal and ventral leaflets

Sporangium covering:  sporocarp wall

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