ON THE GEOGRAPHICAL DISTRIBUTION OF THE NYMPHAEALES

This paper aims to discuss the geographical distribution of the Nymphaeales.It is divided into the following three parts:1.The distribution patterns of nine living genera(three families)in the Nymphaeales.The fossil distribution and the geological date of the geographical distribution of the Nymphaeales genera,the distribution patterns may be divided as follows:A.The tropical distribution pattern a.The genus of tropical Asia destribution: Barclaya b.The genus of tropical America distribution :Victoria c.The genus of tropical Australia distribution :Ondinea B.The temperate distribution pattern d.The genus of temperate Asia distribution: Euryale e.The genus of distribution from Eurasia to north America: Nuphar f.The genus of disjunct distribution between Asia, Australia,America and Africa:Brasenia C.The tropical and temperate distribution pattern g.The genus of disjunct distribution between Asia-Australia and America:Nelumbo h.The Cosmopolitan distribution :Nymphaea i.The genus whose distribution is confined to America:Cabomba 2.The distribution of species According to Takhtajan's view point of phytochoria the numbers of species and endemic species in every region are counted 3.Discussions of the distribution patterns of Nymphaeales There are following problemes:A.The centre of floristic region B.The time of the origin C.The routes of dispersal D.The formation of the modern distribution pattern and reasons for this formation.