Phenology of Exacum bicolor Roxb., an endangered medicinal herb of Kannur and Wayanad districts, Kerala, India

The deciduous herbaceous plant, Exacum bicolor Roxb. (Gentianaceae), is endangered in peninsular India and is distributed in grasslands and scrub forests of Kerala between the elevations of 50 and 1350 m. We investigated four variants on basis of leaf blade shape in the grasslands of Kannur and Wayanad districts, Kerala. The detailed study of these variants for various phenophases such as vegetative growth, leaf flushing, flowering, flowering with fruit development, fruiting and seed dispersal was done during May–November 2009. The development of tillers of all four variants happened in May and the leaf formation took place during June. The flowering period occurred generally during June and July. During August and September, flowering with fruit formation for all variants was followed by the fruiting stage and seed dispersal stage during October and November. As this species completes its flowers-to-seeds period within seven months, collection and sowing of seeds in appropriate time is suggested to enhance subsequent establishment and minimise extirpation.