Observations on the Distribution and Effect of Salinity on a Little Known Plant, Mimulus orbicularis Wall. Ex Benth. (Scrophulariaceae)

Mimulus orbicularis Wall, ex Benth., occasionally found in brackish water lakes, ditches, slacks and often in abandoned ricefields near estuaries and the coastal belt of Eastern India, is a rare aquatic plant. Very often the plants have been found to disappear from the habitat due to some ecological or anthropogenic factors. It is observed that the plant has very little potential for modulating its life cycle strategies in the same habitat. Though populations were recorded in three different localities in India, survival of this species in a parmanent habitat is still a question due to its 'nomadic distribution'. On account of this population behaviour, the collection of this species by many workers in the past has been inadequate. Occurrence of this plant in new localities, extent of distribution and some changes in the morphological characteristics with the change of water salinity and some chemical components of water are discussed in this paper.