Cranfillia fluviatilis, synonym Blechnum fluviatile, is a fern known in the Māori language as kiwikiwi. A herbaceous plant, C. fluviatilis is a "hard fern" of the genus Cranfillia in the family Blechnaceae. It was identified by Patrick Brownsey in 1979.[1] Other common names are star fern, creek fern, kawakawa and kiwakiwa.[2] [1]
Ladderlike fronds of C. fluviatilis measure up to 50cm (20inches) long. Growing in a distinctive ground-hugging rosette shape, its fertile fronds – dark brown and spiky – stand upright from the centre, while the drooping sterile fronds with their nearly round leaflets, form the rosette.[2] As the parent plant ages it develops a short trunk central to a surrounding colony.
The hardy C. fluviatilis requires moist, shaded conditions for optimal growth. A small ground fern, the species is native to New Zealand and southeast Australia, a syntype common throughout the country in damp, shady areas in acidic, moist and boggy soil,[3] beside streams in forest areas.[2] This fern species occurs throughout much of New Zealand's forests, including much of the forested area of North Island; west, north and south coasts of South Island; and Stewart Island/Rakiura; moreover, it occurs in parts of the coastal forests of southeast Australia. Example understory flora associates in the mixed broadleaf/podocarp forests of Rakiura include Austroblechnum durum.[4]
It was collected by William Colenso in December 1841, at the precise locality of woods near Poverty Bay in the North Island.[1]