thermalis is a water lily which blooms at night[2] – its flowers last four days and have four sepals, 19–20 white petals along with yellow anthers and stamens.

thermalis is endemic to the thermal water of the Peţa River, Sânmartin, Bihor County, Romania.

[2] The area is protected as a nature reserve (51.0 hectares (126 acres) in size) and consists of a rivulet along with three ponds.

[2][4] Janos Tuzson proposed in 1907 that this population's unusual location could be explained by the persistent heat provided by the thermal springs could have sustained the population at a pre-ice age time when the plant would have been spreading across the warmer regions of Europe; this theory was corroborated by additional evidence provided by the identification of other endemic species.

[2][5] Alexandru Borza was the Government minister in charge of education (and also a botanist) who made the first push for legal protection and recognition of Nymphaea lotus var.

thermalis – in 1932, the Cabinet of Romania declared the rivulet a nature reserve and the plant a "national monument".

[1] Some sources believe it is a relict, which had survived the ice age due to warm water from the thermal spring in Romania.