Epidendrum radicans  Pav. ex Lindl.  1831

pronounced: ep-ih-DEN-drum RAD-ih-kanz

(Orchidaceae – the orchid family)

common names:  Firestar Orchid, Crucifix Orchid

firespike orchid
inflorescence

Epidendrum is derived from the Greek επι- (epi-), upon, and δενδρον (dendron) a tree; radicans is Latin, taking root.

This is a ground orchid originating in tropical and subtropical South America (southern Mexico, Costa Rica, El Salvador, Honduras, Nicaragua, Panama and Columbia), where it is often seen on roadsides or in grassland, clambering over vegetation. It has also become naturalized in some parts of Africa, Asia and Australia, mostly on disturbed sites. The plant pictured was seen in a roadside garden in Arcadia. Its spectacular flowers are appreciated by some orchid growers, but it takes up too much space for many.

It is a sympodial orchid with long cane-like stems and terminal inflorescences. The stems can be up to 100 cm long, and 1 cm in diameter. The oval leaves are fleshy, and are set at regular intervals along the stem. Fleshy white aerial roots emerge from the leaf axils of new growth, and help entangle the plant with surrounding vegetation.

The inflorescence is a cluster of 20-30 individual flowers. These are small, and a bright orange in colour, with a yellow column. The sepals and petals are ovate, and the lip is 3-lobed. The lobes are fringed and are usually a lighter colour than the tepals, and fade to yellow at the base of the lip. The male and female parts are fused together, and with the lips form a single structure.

It is cultivated as an ornamental, as a garden plant in the tropics and as a pot plant elsewhere, and is also grown for cut flowers. It is impractical to grow it among other plants, due to its spreading nature.

Pollination is by butterflies, whose proboscis can fit into the tube so produced.

How this species attracts its pollinators is a subject of much debate. Some extra-floral nectar is produced, which is believed to attract ants for the purpose of protecting the plants from herbivores. There is no nectar produced within the flowers, and there appears to be no reward offered to the pollinating butterflies. However, they still visit! One theory is that these orchids utilize Batesian mimicry, mimicking other flowers that do offer nectar, and which are often found growing in association with Epidendrum radicans. The problem with this theory is that the plant does not seem to be pollinated any more efficiently when surrounded by the other plants than it does alone. Another theory is that the butterflies are a bit slow on the uptake, and do not realize that there is no nectar until the pollination has been effected.

Whatever the reasons behind the delusion of the butterflies, the plant prospers, and is actually the most common orchid in Costa Rica. It appears to be adapted to infrequent pollination: the plants flower all the year, and individual flowers, which last for about 10 days, are capable of producing many thousands of tiny wind-dispersed seeds.

Photographed in Arcadia, 2013

Page last updated 12th June 2017

 

 

 

 

 

 

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