Plants of
South Australia
Blechnum nudum
Fishbone Water-fern
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Regional Species Conservation Assessments per IBRA subregion.
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Botanical art

Kath Alcock paintings: 5.


Blechnum from the Greek 'blechnon', the name for ferns in general. Nudum from Latin meaning naked.

Distribution and status

Found on Kangaroo Island and southern Mount Lofty Ranges in South Australia, growing along stream banks in shaded gullies. Also found in Queensland, New South Wales, Victoria and Tasmania. Native. Uncommon in South Australia. Common in the other States.
Herbarium regions: Southern Lofty, Kangaroo Island
NRM regions: Adelaide and Mount Lofty Ranges, Kangaroo Island
AVH map: SA distribution map (external link)

Plant description

Erect fern to 1 m tal,l with short trunk and short rhizome. Fronds to 60 cm long are clustered near the tip of the rhizome, with a short, thick, black and shiny stem that is covered with long, dark, shiny scales. The lamina of the frond is divided into pinnae which are longer near the centre of the frond, decreasing in size towards both the tip and base. There are distinct fertile and sterile fronds. The sterile fronds are usually longer and considerably broader than the fertile fronds and are mid-green on the upper surface and paler below, while young fronds are yellow-green. Fruits are dark brown sori along the edge on the underside of the fronds. Seeds are ripe spores are dark brown or black.

Seed collection and propagation

Collect fronds containing sori. Shake fronds to dislodge the spores onto a clean piece of paper. Store spores in liquid nitrogen.