Tuesday, March 24, 2009

Elkhorn Ferns

Platycerium bifurcatum, the Elkhorn fern, occurs naturally in New Guinea and along the coasts of Queensland and New South Wales.
Platycerium is derived from the Greek words platys meaning "flat" and ceras meaning "a horn", referring to the shape of the fronds.
Bifurcatum means to fork into two branches, again, referring to the shape of the fronds.
The Elkhorn fern is an epiphyte which grows on the trunks and branches of trees.
An epiphyte is a plant that normally grows on another plant for support. It is not parasitic.

Each fern is composed of a mass of plantlets. A plantlet consists of a nest leaf, 12-30 cm wide, lying against the bark of the host tree. The nest leaves of neighbouring plantlets overlap one another and become brown and papery with age.
Fertile fronds 25-90 cm long protrude from each plantlet. Spores are produced on the undersurface of the end segments of each frond with spore producing areas coloured tan brown and have the texture of velvet cloth.
I brought a very small plantlet down from my father's garden about 20 years ago and attached it to a huge silky oak (Grevillea robusta) that grows in our garden. It has certainly has thrived and increased in size since then.
They require a shady area to grow in and need to be kept moist. Thankfully they are not prone to attack from many pests and insects except maybe for scale and mealy bugs. But we don't seem to have a problem with those here. Perhaps this is because we have a huge population of ladybirds living in the area and they are a natural predator. Another major reason for restricting the use of insecticides in the surrounding vine blocks.

This and a close relation, the Staghorn fern (Platycerium superbum) are very popular cultivated garden plants in Australia. There are only two other Platycerium sp. growing in Australia.
Platycerium sp. are subject to special regulations to help protect them in the wild. These laws cover activities such as harvesting, propagating, movement of and trade in whole pants and plant parts. When purchasing the plants in nurseries and elsewhere one has to look for those carrying an official government tag to be sure they have been legally obtained.

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