Sempervivum (Brit. /sɛmpəˈvaɪvəm/,[1] U.S. [̩sɛ̃mpeɹ'vivũm]) is a genus of about 40 species of flowering plants in the family Crassulaceae, commonly known as houseleeks. Other common names include liveforever (the source of the taxonomical designation Sempervivum, literally "always/forever alive") and hen and chicks, a name shared with plants of other genera as well. They are succulent perennials forming mats composed of tufted leaves in rosettes.