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The Phytogeography of Caprifoliaceae s. str. with Its Implications for Understanding Eastern Asiatic Flora


The Caprifoliaceae s. str. as here defined consists of 4 tribes and 12 genera:
Caprifolieae (Lonicera, Leycesteria), Linnaeeae (Symphoricarpos, Abelia, Zabelia, Linnaea, Dipelta, Kolkwitzia, Heptacodium ), Diervilleae (Diervilla, Weigela ), Triosteae (Triosteum). Based on chorology, fossil records and dominant woody habit, the family may be considered as a fairly old one and probably originated in the Late Cretaceous or the Early Tertiary. In the light of facts, such as a number of phylogenetic series of Abelia, Triosteum and Weigela occurring in east Asia, Heptacodium, endemic to East Asia, as a link between the tribe Caprifolieae and the tribe Linnaeeae, and existence in East Asia of a high percentage of both palaeoendemic genera and some neoendemics, East Asia seems to be the center
of diversity of the family. Six Eastern Asiatic endemic genera might be grouped under three categories, Heptacodium, Dipelta and Kolkwitzia as palaeoendemics, Weigela as active epibiotics, and Zabelia and Leycesteria as neoendemics. The above inferences are made only on the basis of three main attributes, systematic position of genera isolated or not, their geographical distribution continuous or discontinuous with the closest relatives and the degree of diversification of forms or distinction between species within a genus, without consideration of insufficient fossil records and cytological data.


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