Adiantum diaphanum

Filmy maidenhair fern

Family: Pteridaceae

A rhizomatous perennial fern, growing in rainforest, often along streams or near waterfalls, mainly found on the NSW Coast and slightly into the ranges, extending in Queensland and down into Victoria. Also grows in NZ.

Rhizome short, covered with reddish brown scales; rootlets with small, prominent, brown bulbils.

The fronds grow to about 40 cm tall, are considered compound-pinnate, being divided into 2 or 3 (frond sections made up of segments). The segments (pinnules/leaflets) are to 13 mm long, pale to dark green long and to r mm wide, roughly elliptic to asymmetrical in shape. Terminal growth can have stiff black or brown hairs.

Being a fern, no flowers or fruits are produced.

Spores are produced in sporangia, which are housed in a sorus (plural sori). The sori are produced on the underside of frond segments and follow the segment edges, round to kidney-shaped. There can be up to 8 sori per segment.



In the garden

Grows best in well moist, drained and humus rich soils in dappled light.

Scale can be a problem and Maidenhair aphids.

During winter it needs to be cut back hard to encourage new and attractive green spring growth.

Not cultivated commonly but there are websites suggesting cultivation (see references).

Propagation

Propagation is from plant division or by spores.

Other information

Not likely to be affected by fires. Fire response unknown.

Adiantum – from the Greek adianton (ἀδίαντον) meaning “not wetting” or “un-wet-table”, referring to the fronds’ ability to shed water without becoming wet, likely due to the waxy surface of the segments.
diaphanum – from the Greek diaphanes (διαφάνεs), meaning transparent or filmy, which assumingly pertains to the fronds when held against the light.

Considered Endangered in Victoria but not elsewhere in the wild.

https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Adiantum~diaphanum
https://vicflora.rbg.vic.gov.au/flora/taxon/6d29b789-436a-44f1-ba5f-829f54d29278
https://ppnn.org.au/plantlist/adiantum-diaphanum/
http://www.nzplants.auckland.ac.nz/en/about/ferns/native-ferns/pteridaceae-maidenhair-annual-rock-brake-ferns/adiantum-diaphanum.html

By Jeff Howes