Friday Fellow: Elkhorn Fern by Piter Kehoma Bol

Native from Java to Australia, the elkhorn fern and all other species of the genus Platycerium have a very out-of-the-ordinary appearance for a fern. Growing as an epiphyte, the elkhorn fern has two types of fronds (leaves): basal fronds and fertile fronds.An old specimen of elkhorn fern in Queensland, Australia. Photo by D. Gordon E. Robertson.**The basal fronds are ovoid, kidney- or shield-shaped and grow over the roots and rhizome, protecting them from desiccation by attaching to the substrate. They can reach a length of about 45 cm. They start green but with time dry out and become brown. The upper margin is often more losely attached to the substrate and allows water and leaf litter to reach the roots.

A baby specimen. Photo by Wikimedia user Calvinal*.

The fertile fronds are elongate and forked and grow away from the roots, reaching up to 90 cm in length. They often have a grayish-green color. In mature fronds, the long lobes from their bifurcation bear the sporangia, which are clustered in brownish sori.Fertiles leaves with the brown mark of the sori on the underside. Photo by Wikimedia user Kembangraps.*The elkhorn fern became a very popular garden plant. In tropical and subtropical regions, it can be cultivated outdoors, but in colder climates it only survies indoors since it cannot tolerate temperatures below 5°C. On the other hand, it is quite tolerant to high temperatures and even desiccation. Its basal fronds use Crassulacean Acid Metabolism, a special mechanism used by plants of arid localities to tolerate drought, although the fertile fronds do not seem to be able to do the same.

A specimen growing on a Casuarina glauca tree in Australia. Photo by Peter Woodard.I was not able to find information about the ecological interactions of the elkhorn fern. Who eats it? How does its presence affect the performance of the host plant? Does it have a preferred substrate to grow in its native habitat? For such a popular plant, we seem to know very little about its relevance in the wild.– – –Like us on Facebook!Follow us on Twitter!– – –References:Wikipedia. Platycerium. Available at < https://en.wikipedia.org/wiki/Platycerium >. Access on 24 september 2020.Wikipedia. Platycerium bifurcatum. Available at < https://en.wikipedia.org/wiki/Platycerium_bifurcatum >. Access on 24 september 2020.Rut G, Krupa J, Miszalski Z, Rzepka A, Ślesak I (2008) Crassulacean acid metabolism in the epiphytic fern Patycerium bifurcatum. Photosynthetica 46:156. https://doi.org/10.1007/s11099-008-0026-8– – –* This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.** This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.