DROSERACEAE, a family of dicotyledenous plants, re markable in that all its members are insectivorous. There are five genera and about r oo species. Drosera, a cosmopolitan genus in cluding about 90 species, has three British and seven North Amer ican representatives, known as sundews (q.v.). Dionaea, with a single species, is Venus' fly-trap (q.v.). .4ldrovanda, also with only one species, is a water-plant, lacking roots.