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by K. S. Kugathasan, President, Field Work Centre & Jeyarani Nandakumar, Senior Lecturer, Dept of Botany, University of Jaffna.

We have inherited a rich heritage of fauna and flora from our forefathers. It is our duty to preserve it for our posterity, at least what is remaining, for in the recent past we have done enough damage to our environment affecting many species of plants and animals to the brink of extinction.

Sri Lanka has a rich content of faun and flora that is rich in biodiversity almost equal to that of Malaysia and Indonesia, but not surpassed by any other country. Furthermore there are some living fossils, remnants of the GONDWANIAN fauna and flora depicting the fact that Sri Lanka was a part of that large landmass. But many species of plants and animals are in danger now (Ref. The list of nationally threatened flora of Sri Lanka; The List of Extinct or nearly Extinct Plants in Sri Lanka; same for fauna).

Due to human activity and rarely otherwise species of plants and animals are affected. Species of plants and animals that are common become rare and though very rare - threatened - highly threatened-endangered-become extinct. We have to realize that it is out duty to preserve the gene pool, at least the existing gene pool of our fauna and flora for our posterity. They have every right to enjoy the benefits of the environment as we do. Conservation of the environment with its biodiversity is essential; otherwise human beings too will be affected in due course.

Wild Dioscorea (Kaddu Valli Kodi (T)) is a globally endangered species according to the Red Data Book. There are two species of wild Dioscorea in Sri Lanka, both endemic-Dioscorea Koyamae Jayasuriya and D. Trimeni Prain & Burkill. Both species are highly threatened (Ref. The list of nationally threatened flora of Sri Lanka). There was a plant at Maruthankerni (Vadamaradchy East) that we have seen from the 1960s through 1980s but subsequently it was destroyed by firewood seekers who were more interested in the tree that supported the climber than the importance of the wild Diascorea they destroyed. Recently we have discovered some plants at Sanguvely, a place close to Manipay in the Jaffna Peninsula. These plants must be conserved and at the same time propagation could be tried out.

Wild Dioscorea is a large climber, with slender, cylindrical, twining stems. Most Dioscoreas have winged stems, but the wild species has no wings. The inflorances are pendulous catkins with either male or female flowers.

There may be one too many in each axil of the leaf. Axillary buds may also be modified into aerial tubers (bulbils) that help in vegetative propagation. Leaves are from medium to large in size (3.5-12 inches broad & 3-8 inches length), with long petioles, green in colour, heart shaped (cordate), palmately reticulate venation, shining.

No prickles on stem or leaves. Fruits are winged, dispersed by wind. All Dioscoreas have medicinal value. Cortisone is obtained from the yams of some species. Diosgenin obtained from the yam is used for the manufacture of birth control pills in India.

Rauvolfia serpentina (Ekaveeriya (S), Sarppagntha; Chavanda Aval Pori (T) is a hihgly sought medicinal plant. It is exported and as a result it has become a highly threatened species in Sri Lanka. At present it has become a species that has to be conserved. It belongs to the wet zone of Sri Lanka. It is present in India too.

It is an erect shrub growing to a height of 35-75 cm. Leaves are whorled, three at each node. Leaves are short petioled,elliptical,acute apex, dark green, 8-20 cm in length. Flowers 1.5 cm long with white or pink petals. Flower stalks are deep red. Flowers are arranged in crowded dichasial cymes. Floral buds are curved (hence the Tamil name). Fruits are small, rounded, green when raw & dark purple or black when ripe. Because of its importance, this plant is cultivated in India. It could be grown from root cuttings, stem cuttings & seeds.

As regards its medicinal values, this plant is very important. Dried roots with bark are used. This plant is supposed to have been in use in ayurveda for more than 4000 years. The roots contain many alkaloids from which drugs are obtained that have a sedative or hypnotic effect. It is mostly used to control high blood pressure. It is also used to cure insanity.

This drug has tranquillizing qualities too. The roots are also used to cure bowel disorders & fever. Rauvolfia tetraphylla/ R.canescens Sarpragantha\ Chavanda Avalpori (T)) is another species belonging to the genus Rauvolfia. It has the same qualities as R. serpentina as far as medicinal properties are concerned. Details regarding the distribution of this plant in Sri Lanka is not known.

We have discovered some plants in Jaffna, but are very rare. Its position is not known, it is not known whether it is indigenous, or introduced for its medicinal values or for ornamental purposes. Distribution of this plant in the Peninsula too is not known.

This plant grows from small to medium heights & is a much-branched shrub. Branches are usually in pairs (false dichotomy). Leaves are in whorls, four to each node (hence the species name) 2 large, 2 small, pale green, elliptical, acute apex, small to medium size. Inflorescence dichasial cyme. Flowers & buds are small, light yellow curved. Fruits are small, round, green when raw, bright red when ripe. Seeds dispersed by birds.

We are fortunate that some of these threatened species are there for it is for us to conserve them before they become extinct. Dedicated to the Genetic Resources Center for their attention and action towards the conservation and propagation of these species of plants. Unless immediate action is taken these may disappear from the Sri Lankan environment.

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