The genus Murdannia Royle (Commelinaceae) represents 21 authorised species in South India. The distribution and ecology of the genus in South India has been analysed. The analysis showed that the habitat preference as laterite substrate (43%), grassland (29%), marshes (14%) and rocky substratum (9% each) and streamsides (5%). The altitudinal preference indicates that 38% of Murdannia species found in 700 – 1000 m MSL, 28% in 1-70 m MSL, 19% in 40 – 700 m MSL and 5% each in 1000 – 1200 m MSL, 1 – 1000 m MSL and 70 – 1000 m MSL. The population density of the species indicates that 62% Murdannia species belongs to rare category, 24% belongs to common category and 14% belongs to vulnerable category. Among this, 81% of species prefers exposed conditions and 19% prefers shade. It is concluded that the speciation and diversification of the genus Murdannia in South India strongly correlates with altitude and climatic conditions.