The red list of threatened Characeae 2010 is the first list of endangered macroalgues published in Switzerland. It contains a list of all Characeae identified on Swiss territory, classified by category of threat according to the IUCN criteria. Out of 25 species identified in Switzerland to date, four species are regionally extinct (RE), four are critically endangered (CR), six are endangered (EN), and six are vulnerable (VU). More than 87 % of Switzerland's stonewort species with sufficient data were included on the red list, 17 % are extinct in Switzerland, and 70 % are species at extinction risk and listed in categories CR to VU.