It's leaflets have veins that are dichotomously branched but are marginally united to form a loose reticulum. The leaves that are submerged lack a cuticle and have smaller blades. Marsilea also has adventitious roots that emerge at the nodes. In the life cycle of Marsilea the sporophyte is dominant. Marsilea has specialized structures that their sporangia grow in called sporocarps.
Sporocarps are soft and green when they first start to develop, but then turn hard and brown.
The gametophyte of Marsilea are small and do not live for long periods. They have both microgametophytes and megagametophytes. The microgametophyte have very small antheridie with nine sperm cells. The megagametophyte only have one archegonium which is sometimes called a bell. The genera Salvinia and Azolla make up the order Salviniales.