AFRICAN

ORCHIDS

Epiphytic Orchids of the Seychelles

on Mah Island SeychellesThe Orchid family is the largest plant family in the world and contains over 30 000 species dispersed throughout the world except Antarctica. Many orchids have elaborate and beautiful flowers and are cherished the world over. Many exotic orchids are grown in gardens throughout the Seychelles, most of them coming from Asia, such as the Spider orchid Arachnis flos-aeris, Vanda Papilionanthe teres, ground orchid Spathoglottis plicata and the red Renanthera orchids, all of which grow well in a tropical garden.

The Seychelles archipelago is not blessed with as diverse an orchid flora as the larger islands of the Comoros, Mascarenes and Madagascar, but Seychelles does have a number of unique and interesting species, some of which are endemic. Many species are widespread throughout the Islands of the Western Indian Ocean, Africa and even Asia.

The total list of Seychelles orchids stands at a possible 30 native species and 6 of them are possibly considered to be endemic to the Seychelles islands (Govaerts, Kew World Checklist of Monocotyledons Database), but a number of these have not been confirmed as yet. Some old accounts of the flora, dating back to the 1800s, list species which could easily have been misidentified or confused with other related species. As a consequence more work

Of the 30 possible native species 19 are epiphytic (growing on trees), climbers or lithophytic (growing on rocks) (Govaerts, Kew World Checklist of Monocotyledons Database). Many go unnoticed as they are small inconspicuous plants with tiny flowers, growing high up in the mountains, shrouded in mist and surrounded by mosses. It is likely that many people will recognize only two species: the national flower of the Seychelles Angraecum eburneum (Tropicbird orchid / Orkid payanke) and the leafless Vanilla phalaenopsis (Leafless vanilla / Lavannir sovaz) which is often seen with its green stems snaking over rocks and up trees. Both these plants produce the largest flowers of all the native orchids, which has undoubtedly led to the low numbers of Tropicbird orchids one now sees in more accessible areas.

The other 16 species are all small flowered plants, two of which are possibly endemic. The unique Hederorkis seychellensis is a plant of mountain forests, growing amongst mosses on trees, and producing small sprays of bright pink to white flowers. It is related to the other possible endemic Polystachya bicolor, (awaiting confirmation after a full revision of the Genus) which is much more common and widespread, also found growing in the mountain forests but sometimes in full sun on exposed boulders. It produces erect clusters of bright pink waxy flowers.

The Bulbophyllum genus is an interesting and large group of orchids containing over 18 000 species, of which three widespread species occur in the Seychelles. They all produce small bulbs along a rhizome and have one or two leaves on top of each bulb. The flowers are small and often produce a foul-smelling perfume to attract flies to pollinate them. Which includes the Tropicbird orchid, produce a fragrant perfume in the evenings, to lure moths to sip their nectar and pollinate the flowers. The nectar is contained in a long spur on the often beautiful white or green star-shaped flowers.

Unfortunately, increasing numbers of exotic orchids are naturalized in the forests of the Seychelles.

The most widespread of these is the Pigeon orchid Dendrobium crumenatum which produces clusters of white flowers that only last for one day. It is often self-pollinating, which greatly increases its spread through wind-dispersed seeds, so that it now occupies almost all parts of Mahé, from the coast right up to the very top of the mountains. Indeed many areas which should hold numbers of native species now contain rampant populations of Pigeon orchids. I have even noticed that the ground orchid Spathoglottis plicata is present in many forests on Mahé and the commercial Vanilla, Vanilla planifolia, has survived and spread in the surroundings of old plantations on Mahé and Praslin. These exotic orchids may potentially pose a problem to native orchids because they occupy the same special microhabitats on trees, rocks or on the ground as the native species and may compete with them for these particular places.

Although epiphytic orchids are not easy to see, even when you get up into the mountain forests, with a little patience and keen eyes it should be possible to enjoy their intricate beauty.