INVASIVE ALIEN WEEDS AND THEIR ETHNO-BOTANICAL IMPORTANCE OF VIJAYAMANGALAM VILLAGE, ERODE DISTRICT

Uma, G.,* S. Jagathes Kumar and V. Balasubramaniam Department of Botany, Kongunadu Arts and Science College, Coimbatore. *E.mail: umaphd430@gmail.com The present study deals with comprehensive list of Invasive alien plants of Vijayamangalam village, Perundurai taluk, Erode district with background information on family, habit and nativity. A total of 50 invasive alien species under 40 genera, belonging to 18 families have been recorded. While in life form analysis, the herbs (40 species) are dominant, followed by shrubs (6 species), Climber (2 species), Trees (2 species).


INTRODUCTION
Alien species are non-native or exotic organisms that occur outside their natural adapted ranges and dispersal potential. Many alien species support our farming and forestry systems in a big way. However, some of the alien species become invasive when they are introduced deliberately or unintentionally outside their natural habitats into new areas where they express the capability to establish, invade and out compete native species. International Union for Conservation of Nature and Natural Resources (IUCN) defines Alien Invasive Species as an alien species which becomes established in natural or seminatural ecosystems or habitat, an agent of change, and threatens native biological diversity. These invasive are widely distributed in all kinds of ecosystems throughout the world, and include all categories of living organisms. Nevertheless, plants, mammals and insects comprise the most common types of invasive alien species in terrestrial environments (Raghubanshi et al., 2005). Exotic weeds cause loss of biodiversity including species extinctions and changes in hydrology and ecosystem function. Some alien or exotic weeds could affect ecosystem properties by bringing nutrient to the surface from deep in the soil, thus serving as "pumps'' which keep high levels of essential nutrients in circulation.
Many agriculturists have recognized that weeds despite their nuisance value do at times serve some useful purpose. Weeds often provide a protective cover against surface washing and run off. Moreover weeds are frequently used in the form of mulch around cultivated plants. Some antibiotics, as well as bio pesticides have been extracted from weeds. Apart from this many weeds are used as high poison, green manures and pollution indicators.
Weeds are comprised of the more aggressive, troublesome and undesirable elements of the World's vegetation. More than 80% of the developing world continues to rely on traditional medicines predominantly plants, for primary healthcare. The global demand for herbal medicine is not only large, but also growing. The market for Ayurvedic medicine is estimated to be expanding at 20% annually in India (Jeeva et al., 2006).

Study area
The study area Vijayamangalam village located in Perundurai taluk under Erode district. The major occupation of the peoples is agriculture and Hand loom weaving. Erode experiences hot and dry weather throughout the year. The temperature ranges from a maximum of 96°F (36°C) to a minimum of 80°F (27°C) Field trips were made during the study period 2012-2013. The entire area was covered at different seasons. Specimens collected from the study area were identified carefully using the Flora of the Presidency of Madras by J.S. Gamble & C.E.C. Fischer , Flora of TamilNadu Carnatic by K.M.Mathew, (1983). Identity of the plants was confirmed after critical studies with reference to authentic materials available in the Herbarium of The Botanical Survey of India, Southern circle, Coimbatore (MH) and Herbarium of Kongunadu Arts and Science College, (KASCH).

RESULTS
The weeds, which are best known and most highly regarded in traditional medicine, are enumerated with botanical name, local name (in Tamil), family, medicinal uses and nativity. 50 medicinal weed species belonging to 18 families and 40 genera have been recorded (Table-1). Amaranthaceae was the dominant family with 12 species, followed by Asteraceae (7 species), Malvaceae, Caesalpinaceae, Asclepiadaceae, Convolvulaceae and Nyctanginaceae (3 species each). 5 families were represented by 2 species and 6 families represented by single species. Most of the medicinal plants are common are growing in wild condition as weeds.

DISCUSSION
Alien species are non-native or exotic organisms that occur outside their natural adapted ranges and dispersal potential (McGeoch et al., 2010). Many alien species support our farming and forestry systems in a big way. However, some of the alien species become invasive when they are introduced deliberately or unintentionally outside their natural habitats into new areas where they express the capability to establish, invade and outcompete native species. International Union for Conservation of Nature and Natural Resources (IUCN) defines Alien Invasive Species as an alien species which becomes established in natural or semi-natural ecosystems or habitat, an agent of change, and threatens native biological diversity. These invasive are widely distributed in all kinds of ecosystems throughout the world, and include all categories of living organisms. Nevertheless, plants, mammals and insects comprise the most common types of invasive alien species in terrestrial environments (Raghubanshi et al., 2005).  Abrus precatories Fabaceae climber Skin related problems, Scratches from pet animals, Abdominal Pain Indonesia To treat urinary problems. A poultice made from the roots is applied to 9.
Crotaleria pallida Fabaceae Shrub painful swelling of joints, and an extract of the leaves is taken as a vermifuge.

Africa
Leaf is useful in night blindness and leaf paste is used in cuts, boils, 10. Cassia tora Caesalpinaceae Herb burns and as antiseptic treatment. Seed is given in stomach pain. Root is given in fever and abnormal child growth.