Hydrocharis

Hydrocharis is one of 16 genera in the aquatic monocotyledon family Hydrocharitaceae and consists of three species, Hydrocharis morsus-ranae L., H. dubia (Blume) Backer, and H. chevalieri (De Wildeman) Dandy. ^{7 , 45} H. morsus-ranae is native to much of Europe and is known from a few locations in the Middle East and U.S.S.R. ⁷ It was also introduced into Canada in 1932. ²⁶ It subsequently spread from the initial population in Ottawa, Ontario and is now found throughout much of southern Ontario ⁵ and has recently been reported from several locations in New York state in the U.S. ³² H. dubia is native to the Far East and Australia while H. chevalieri is restricted to west central Africa in its distribution. ⁷ Flowering in Hydrocharis is of particular interest because it represents one of the few primitive en-tomophilous genera in a family which shows a trend towards highly specialized systems of hydrophilous pollination. ^{6 , 21 , 40} Furthermore, the developmental nature of the inferior ovary is a point of some relevance, since this feature is present only in the Hydrocharitaceae and nowhere else in the Alismatidae. ^{13 , 45}