Taxonomy and ecology of obnoxious weed Alternanthera philoxeroides Grisebach (family Amaranthaceae) on spore germination in Ampelopteris prolifera (Ketz.) Cop.
Alternanthera philoxeroides, the alligator weed is an invasive species that is native to South America. From the invasive point of view A. philoxeroides has proved to be second in the world after Parthenium. The plants are cosmopolitan in distribution. Because of its invasive nature, high rate of vegetative reproduction, as well as the ability to produce several allelochemicals, it has gradually threat to our biodiversity. The present paper deals with the distribution of A. philoxeroides in the district of Midnapore and its association and effect on other crops. It also deals with the studies of the effect of aqueous extracts from various plant parts (inflorescence, stem, root and leaves) of A. philoxeroides on the spore germination of the edible pteridophytes Ampelopteris prolifera. Stem and root extracts were found to exhibit maximum allelopathic potentiality causing a decrease in the spore germination percentage than leaf extract. Increase filamentous growth and decrease rhizoidal growth has been attributed to the presence of alkaloids and phenols in the extracts of A. philoxeroides. It has been found that these toxic substances are synthesized in the leaf but gradually they are translocated to the various plant parts like stem and roots.