Habit: Marsilea nashii grows in stoloniferous mats with stems arising every 2-3 cm. The pinnae are arranged in groups of 4 at the end of each stem. Each pinna is pubescent with a narrow base, flattened apex and entire margin.
The individual sporocarps arise at the base of each stem and are covered in pubescence. Each sporocarp with have up to 12 pairs of sporangium each with up to 10 macrospores or numerous microspores.
Habitat: Marsilea nashii grows in sandy soil in ephemeral Fresh Water Wetlands typically with Sabal palmetto.
Distribution: Marsilea nashii grows in the southern Lucayan Archipelago and Cuba.
Medicinal/Cultural/Economic usage: Marsilea nashii is not used medicinally in the Lucayan Archipelago.