The Genus Stratiotes L. (Hydrocharitaceae): from Many to One

The genus Stratiotes L. (Hydrocharitaceae) includes 20 known species, most of which had become extinct by the Pleistocene, with only Stratiotes aloides L. surviving to the present day. The study examines the genus Stratiotes, and provides its integrative morphological, ecological, geographical analyses and geographical range reconstructions. A detailed examination of the seed morphology and statistical evaluation of key diagnostic characteristics are provided. The morphologically evaluation performed allowed a conclusion, that the strongest morphologically isolated species are S. imperfectus and S. tavdensis (members of genus Najas L.), S. inversus, S. minutissimus being the most isolated form. Stratiotes bromeliiformis and S. schaarschmidtii are unlikely to be members of the family Hydrocharitaceae. The data on the type material for all the species examined is provideded. Lectotypification for the four species has been carried out. The mean temperature of the coldest quarter and the precipitation of the driest month and of the coldest quarter had the greatest impact on the modeled spatial distribution patterns. These findings offer valuable insights into the evolutionary history and paleobiogeography of the genus.