The genus Marsilea comprises amphibious ferns known for their remarkable adaptability to varied aquatic and semi-aquatic habitats. Numerous species of Marsilea exhibit morphological changes depending on their habitat or geographic location. This study investigates morphological and ecological variation across eight natural populations of Marsilea from distinct habitat types within Kota District, Rajasthan, India. Extensive field surveys were conducted across diverse habitats, including wetlands, canal systems, agricultural fields, and temporary water bodies, during different seasons. A total of 80 specimens, comprising aquatic, semi-aquatic, and terrestrial forms, were assessed for key morphological traits, including leaflet length and width, petiole length, sporocarp characteristics, and growth patterns. Environmental parameters, including soil type, water availability, and anthropogenic pressures, were also recorded to understand habitat influences. The findings reveal significant intra and interspecific variations in response to local ecological conditions, highlighting the phenotypic plasticity of Marsilea populations. Additionally, the study underscores the role of habitat disturbance and climatic factors in shaping the distribution and vitality of these species. The results contribute valuable insights into the adaptive strategies of Marsilea spp., and they show that Marsilea minuta is more ecologically versatile and stress-tolerant, making it more adaptable to different environmental conditions than Marsilea cf. coromandelina in the semi-arid landscape of Kota district, and provide a baseline for future conservation and ecological studies.

Keywords:Marsilea; Comparative Analysis; Morphological Variation; Habitat Ecology; Kota District; Rajasthan; Phenotypic Plasticity