The Latvian Botanical Society has awarded this honorary title to the cavernous crystalwort (Riccia cavernosa).
Riccia cavernosa grows in rounded rosettes up to 3 centimeters in diameter, composed of many lobes that are oblong or rounded, and widest above the middle.
The crystalwort prefers damp soil, in places prone to flooding, near lakes and rivers, sand pits, on muddy roads and on dunes. The moss can be seen all year round if there is no frost and snow.
The species is especially protected in Latvia as there are few observations of it. But if you do happen to come across it, report it at Dabasdati.lv.