Recognition: medium to large ground fern, with once-divided fronds. Like most hard ferns (Blechnum), the sterile and spore-producing fertile fronds look markedly different. The segments of the fertile fronds are very narrow and black or brown. In the sterile fronds, the segments in the lower part of the frond are stalked and reduce in size until they are short lobes. The scales on the frond are pale brown but usually have an obvious dark centre.
Distribution/ecology: only found in New Zealand. Throughout, within and on the margins of forests and swamps. Often on roadside banks. Kiokio is one of the most frequently seen ferns in New Zealand.
Relationships: Green Bay kiokio (Blechnum triangularifolium), mountain kiokio (Blechnum montanum), small kiokio (Blechnum procerum), and swamp kiokio (Blechnum minus) are all similar. They can be distinguished by the shape and size of the sterile fronds, and scale colouration.
18 species of Blechnum are indigenous to New Zealand. They are collectively known as hard ferns, due to the tough texture of their fronds. They belong to the Blechnaceae fern family, whose other indigenous representative is Doodia, which has five indigenous species in New Zealand. The sterile and fertile fronds of Doodia (rasp ferns) are either similar or only somewhat dimorphic.