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Topic: hound’s tongue

Is part of topic Common New Zealand ferns

kowaowao, paraharaha
Microsorum pustulatum

Recognition: smallish fern that creeps extensively, either along the ground or up tree trunks.  The frond is glossy lime-green, with several pairs of lobes that are noticeably broader in sterile fronds compared to fertile fronds.  The sporangia (which produce spores) are aggregated into circular, unprotected, orange sori away from the margins of the undersides of fertile fronds.  The sori visibly bulge on the uppersides of the fronds.  The creeping rhizome is thick (diameter up to about 10 mm), with appressed dark scales.

Distribution/ecology: occurs in New Zealand and Australia.  In New Zealand it is found throughout, in forest and open habitats.

Relationships: three Microsorum species occur in New Zealand.  Fragrant fern (Microsorum scandens) extends from northern North Island to central South Island, and is also found in Australia.  Fragrant fern is distinguished by its duller fronds that have narrower lobes, and by its much narrower rhizome (diameter less than 5 mm).  It is restricted to more benign environments (warmer, wetter) than hound’s tongue, but the two commonly occur together.  Microsorum novae-zealandiae is found in the uplands of the North Island.  Its fronds have longer and narrower lobes, and erect, orange-brown scales on its rhizomes.

Microsorum is a member of the Polypodiaceae fern family.  The other indigenous members are Ctenopteris, Grammitis, Loxogramme, and Pyrrosia.

NZ eFlora treatment for Microsorum pustulatum.

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