Marsilea crenata

Marsilea crenata is a widely-spread water clover distributed in South-East Asia and Australia (Northern Territory, northern and central-eastern Queensland). It is found in shallow water and on drying-out mud, amongst others in rice paddies.
M. crenata cannot be clearly discerned from Marsilea minuta, and might even belong to that species (Nagalingum & al. 2007).

In trade, you often see the names M. crenata, M. hirsuta, M. exarata, M. drummondii and M. quadrifolia, however, it is not sure whether the respective plant was identified correctly. Most species of the genus Marsilea can only safely be identified in their emersed form by means of their sporocarps (spore-containing fruit).
Please see Marsilea spp.