Hemianthus micranthemoides

The plant known under the name Hemianthus micranthemoides for decades was recently (2011) identified as Hemianthus glomeratus by Cavan Allen (USA), a species endemic to Florida.
Real H. micranthemoides however has probably never been cultivated as an aquarium plant. It is considered missing and probably even extinct in nature. It was last found in the wild in 1941. Hemianthus micranthemoides was distributed along the Central Atlantic Coast of the USA, from New York to Virginia, in the intertidal zone of river estuaries, highly specialised to these habitats.

Please see Hemianthus glomeratus.