Land and water forms: Physiological aspects

摘要: Although the great majority of vascular plants are restricted to typical land habitats, a considerable number, water or hydrophytes, attain their optimum development in various aquatic environments. Such hydrophytes well characterised both morphologically and physiologically, constitute distinctive biological group, but taxonomically they very heterogeneous, including several genera pteridophytes representatives from wide range angiosperm families. It is generally accepted that taxonomic groups have originated independently ancestors consequently habit has been secondarily acquired.