The king fern grows alongside streams, in rainforest gullies and other wet spots in tall open forest. Occasionally it is found in drier sites in rock crevices among sandstone or granite cliffs or rockfaces. In
South Australia,
Todea barbara is increasingly rare, with small groups occurring in just a few disparate localities in the
Mount Lofty Ranges. The largest remaining stand was in Uraidla on private property, on the upper reaches of "Deep Creek", a tributary to Sixth Creek in the Torrens Catchment. In the 1970s, many ancient two metre tall fern trunks were removed by a plant poacher at night, possibly under the mistaken belief that they were tree ferns, which can transplant readily. Mature king ferns do not. There are a few remnants in this gully today and some local native plant specialists have propagated plants from spores from this site, which may be grown in the home garden or planted along creek edges. In New Zealand, the king fern is restricted to Northland, where it is found from North Cape to Whangarei and Kai Iwi Lakes, and Three Kings Islands. ==Cultivation==