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| Sunday, 18 December 2005 |
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Junior Observer |  |
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Sinharaja's flora - Plants that grow on plants
I hope you enjoyed the different aspects of Sinharaja, we discussed during the previous weeks. Remember what we learnt about Sinharaja's flora? But there is one important area we still have not talked about. So, we will explore Sinharaja's epiphytes - mosses, lichens, orchids and ferns, this week. What are epiphytes? They are plants which settle and grow on other plants. They spread through light and numerous seeds or spores carried by wind. Once a favourable place is found, these seeds or spores start growing and taking root. Life on trees is not easy for epiphytes. For they have no soil or water to grow in. Therefore, these plants invent various modifications to get water and nourishment. When it comes to tropical rainforests such as Sinharaja, where moist conditions prevail throughout the year, epiphytes thrive. They can be seen in the little crevices on rough barks, in the forks of branches and in the pockets formed at the base of palm leaves. Lichens and mosses are the most common epiphytes that could be seen anywhere. They sometimes grow on trees to an extent, where the bark is covered by a half inch thick moss growth. They are at an advantage as epiphytes because they can live without water for short periods. Orchids form another category of epiphytes found in Sinharaja. You will wonder at the beauty of their flowers of various hues, shapes and sizes. Sinharaja holds four very special and endemic species of orchids, three of them growing as epiphytes and one on the ground. (1) Dendrobium diodon is a small endemic and rare orchid. Growing on rough bark, it spreads its collection of roots to stabilise its position on the bark. Its flowering season lasts about three months from August. Its small flowers are arranged in a inflorescence(bunch). This plant is now limited to Sinharaja, Hakgala and peak wilderness protected areas. (2) Podochilus saxatilis, another endemic orchid growing in Sinharaja could be found on large trees that reach up to the forest canopy. With small leaves, the plant looks like a inflorescence of paddy. During the flowering season, from March to October, minuscule (very small) flowers could be seen on each leaf tip. (3) Podochilus falcatus is an endemic orchid, but is commonly seen in Sinharaja, on trees and rocks. This plant also looks much like P.saxatilis. However, the difference is the clusters (bunches) of flowers that could be seen at the end of leaf tips instead of single flowers, and the size of the flower, which is larger than that of P. saxatilis.
Growing at the ground level as well as on trees, ferns also form an important part of epiphytes. Ferns found in Sri Lanka are special because some of them come from the times dinosaurs were living on Earth. These ferns are called 'living fossils' because the first such ferns were found on Earth about 100 to 200 million years ago. Over 135 fern species have been found in Sri Lanka out of which, 58 are endemic. In Sinharaja many of the species could be found at the ground layer and on trees in the forest canopy. Benduru (Drynaria quercifolia), Maha Hedaya (Huperzia phlegmaria), Kuda Hedaya (Huperzia squarrosa), Patidhathu (Ophioglossum pendulum), Val Meda (Angiopteris evecta) and Kekilla (Dicranopteris linearis), and some Selaginella and Cyathea species are some of the ferns found in Sinharaja. (1) Ophioglossum pendulum - an epiphyte could be seen on very large trees. The ribbon like leaves grow upto about two to three feet. (2) Huperzia phlegmaria - a well-known fern (Maha Hedaya). Growing on Sinharaja's trees, it is a rare plant valued for its medicinal qualities. - Vimukthi |
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