Cranfillia fluviatilis

Ladderlike fronds of C. fluviatilis measure up to 50 cm (20 in) 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.[3] 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,[4] beside streams in forest areas.[3] 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.[5]

It was collected by William Colenso in December 1841, at the precise locality of woods near Poverty Bay in the North Island.[2]