Drosera (sundews)

Drosera is a scientific botanical genus name established in Linnaean taxonomy and derived from the Greek δρόσος (drosos), meaning "dew" or "dewdrops," a reference to the glistening mucilage droplets produced by the glandular trichomes on the leaves. The English common name "sundew" is derived from the Latin ros solis, "dew of the sun." The genus has been treated historically within modern botany as one of the largest carnivorous plant genera and has been the subject of scientific observation (notably by Charles Darwin among others).

Members of the genus Drosera are perennial (rarely annual) herbaceous plants forming prostrate or upright rosettes, typically ranging from about 1 cm to 100 cm in height depending on species, with some climbing forms producing scrambling stems to several metres. Their leaves are covered in stalked glandular trichomes (often described as tentacles) tipped with sticky mucilage droplets that glisten like morning dew. Growth forms include temperate rosette species (which may form hibernacula and die back in winter), subtropical evergreen types, Australian pygmy sundews with dense crown hairs, tuberous species that form underground tubers to survive dry seasons, and climbing species found in certain sections.

Drosera species are carnivorous plants that attract, capture and digest primarily small insects using stalked mucilaginous glands on their leaf surfaces. Small prey are drawn by sweet secretions from peduncular glands; on contact they become entrapped by sticky mucilage. Many Drosera species can move their tentacles to further enfold prey. Captured animals usually die within minutes to hours as mucilage envelops them; the plants secrete digestive enzymes — including esterase, peroxidase, phosphatase and protease — which dissolve the prey and allow absorption of nutrients through the leaf surface. This carnivory supplements the poor mineral nutrition of the soils in which they grow.