Waterwheel plant

Appearance

''Aldrovanda vesiculosa'' is a rootless aquatic plant. Seedlings develop a short protoroot; however, this fails to develop further and senesces. The plant consists of floating stems reaching a length of 6–40 cm. The 2–3 mm trap leaves grow in whorls of between 5 and 9 in close succession along the plant's central stem. The actual traps are held by petioles which hold air sacs that aid in flotation. One end of the stem continually grows while the other end dies off. Growth is quite rapid per day in Japanese populations), so that in optimal conditions a new whorl is produced once or more each day.

Naming

While the genus ''Aldrovanda'' is now monotypic, up to 19 extinct species are known in the fossil record. While the species displays a degree of morphological plasticity between populations, ''A. vesiculosa'' possesses a very low genetic diversity across its entire range.

Distribution

''Aldrovanda vesiculosa'' is the most widely distributed carnivorous plant species, native to Europe, Asia, Africa, and Australia. ''Aldrovanda'' is spread mainly through the movement of waterfowl: plants sticking to the feet of a bird are transported to the next aquatic destination on the bird's route. As a result, most ''Aldrovanda'' populations are located along avian migratory routes. Throughout the last century the species has become increasingly rare, listed as extinct in an increasingly large number of countries.

Status

''A. vesiculosa'' has declined over the last century to only 50 confirmed extant populations worldwide. These are spread across Europe, Africa, Asia, and Australia. It is kept by hobbyists.

Habitat

''A. vesiculosa'' prefers clean, shallow, warm, standing water with bright light, low nutrient levels, and a slightly acidic pH . It can be found floating amongst Juncus, reeds, and even rice.Die Wasserfalle bedarf äußerst sauberer, seichter, heller und warmer stehender Gewässer, die zugleich nährstoffarm und schwach sauer sind. Sie ist zwischen Binsen oder Schilf, aber auch Reis frei schwimmend zu finden. Mit zunehmender Verdichtung des Bewuchses ihres Areals geht die Wasserfalle dann wieder zurück und taucht an anderen Stellen wieder auf. Sie reagiert empfindlich auf den Befall durch Algen.

Evolution

''Aldrovanda vesiculosa'' was first mentioned in 1696 by Leonard Plukenet, based on collections made in India. He named the plant ''Lenticula pulustris Indica''. The modern botanical name originates from Gaetano Lorenzo Monti, who described Italian specimens in 1747 and named them ''Aldrovandia vesiculosa'' in honor of the Italian naturalist Ulisse Aldrovandi. When Carl Linnaeus published his ''Species Plantarum'' in 1753, the "i" was dropped from the name to form the modern binomial.