Marsilea
Plant is small and can be semi or fully aquatic.The plants can be seen on the surface of water, with the roots submerged in the mud.
Not Threatened in Western Australia
The fronds contain between two to four leaflets, located at the apex of a long and thin stipe. Immature fronds are circinate, while sterile fronds will appear as long and thread-like. Leaflets are hairy, obovate or glabrous. Fronds grow erect from the mud, or to the surface of water. It is the leaflets on the fronds that can be seen on the water's surface. Leaflet size can range from 7 mm to 20 mm. The rhizomes can be long, slender and creeping; or they can be fibrous and thick with hairs present. Rhizomes are submerged deep in the mud or in soil. Reproductive structures appear as bean-like structures called sporocarps. Sporocarp is stalked, rising from the base or along the stipe, either located in groups or can be solitary. The sporocarp is physically woody and hard, with one to to basal teeth present, and visibly having dense hairs. Sori are numerous and are attached to a gelatinous ring which becomes extruded when the sporocarp bursts at the stage of maturity. The sporocarps can either be sessile or pedunculate, containing numerous microsporangia (male spores) or megasporangia (female spores) in the same sorus. Megaspores are singular,and microspores appearing numerously.
The Family Marsileaceae is a heterosporous fern, along with the Family Salviniaceae. Heterosporous means that there are two types of spores produced, microsores (male) and megaspores (female). Marsileaceae fall within the core leptosporangiate ferns, which include heterosporous ferns, polypods and tree ferns, all which are monophyletic.
Marsileaceae and Salviniaceae were once thought to be independent, however a sister group relationship has been confirmed between the two Families. The clade from which Marsilea derives from, is made up of three lineages, with several genera representing tree ferns and 15-30 families classifying polypods.
Distributed through most of Western Australia.
Habitats include semi-aquatic and aquatic environments, can be seen in rivers and drainage basins.
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