Drynaria rigidula

basket fern


Drynaria rigidula

(Sw.) Bedd. 1869

pronounced: dry-NAR-ee-uh rig-ID-yoo-luh

(Polypodiaceae — the fern family)


common name: basket fern

native 4Drynaria comes from the Greek δρυς (drys), the oak tree, referring to the oak-shaped fronds; rigidula is from the Latin rigidus, stiff, with rigidulus its diminutive– a little stiff.
Basket ferns occur in eastern Queensland and north-eastern NSW, although they are very rare in NSW – indeed, they were thought to be extinct there, and have only recently been rediscovered in tiny numbers and in only 3 locations. It is a very adaptable species: it grows on trees in rainforest and tall open forest, where it can form huge colonies high in the canopy, where it often serves as shelter for amethystine pythons (Morelia amethistina) and scrub pythons (Morelia kinghorni). In the 19th century, the Norwegian explorer Carl Sofus Lumholtz observed indigenous peoples scaling trees to reach colonies of these ferns for the purpose of hunting the pythons. The fern can also grow on rocks in more open areas, where it can form huge clumps. It grows as a much smaller plant sporadically amongst rocks in open forest, where it is probably kept from developing into big clumps by regular fire. It can also be found growing in the ground in poor sandy soils of old dune formations in locations such as Hinchinbrook Island in Queensland. This last form is a little different from the others, in that it has considerably larger basal fronds – indeed, it may be taxonomically different.

The fern has two types of frond: fertile foliage fronds and sterile nest fronds. The dark green foliage fronds are large, anything up to 120 cm or even longer, with elongated stalks. They are deeply lobed or pinnate, winged, and bear sori on the lower surfaces. The sori are round, 1 – 2 mm in diameter, in one row on each side of the costa.

The nest fronds, narrowly ovate to ovate, are smaller rounded leaves, basal to the foliage fronds. They do not bear sori, and persist after turning brown and dying. They form a sort of basket around the base of the plant, and collect litter and organic debris that decomposes into humus to provide the plant with nutrients.

Drynaria possess specialized nectaries on the bases of the frond lobes or the undersides of the fronds. The produced nectar is rich in sugars and amino acids. The function of the nectaries may be to attract ants or other organisms, or they may merely be excretory organs for exuding surplus metabolic products.

The rhizomes that attach Drynaria to tree or rock are about 1 cm thick, creeping, and densely covered in brown scales.

Basket ferns are found from equatorial Africa to tropical south and east Asia and Oceania, as well as in Australia. The ferns photographed are growing on Phoenix palms in the parkland at the southern end of Picnic Bay.


Photographs takin in Picnic Bay 2014
Page last updated 16th December 2018