Morphological And Systematic Studies Of The Fruits Of The Family Cornaceae And Related Taxa

The fruit and seed structures of 27 species and 3 varieties reprenting 8 genera of Cornaceae and 7 species from 6 genera of Araliaceae in China were studied in the paper using GMA method. The fruit and seed shapes and trichome types were observed, and their structures were deeply studied. The results showed that the taxa studied were divided into three groups. Group 1. Araliaceae: The fruits are with two carpels which are bilaterally compressed with multicellular trichomes. The fruit ribs are prominent, The oil tubes and drues crystals are dispersed in the mesocarp. The endocarps of the fruit are separated each other and composed of fibers. The ventral vascular bundles appear in between two carpels. Group 2. Helwingia: The fruits are berry with obvious ribs and trichomes are ansent. The endocarps of the fruit are separated each other and composed of stone cells and fibers. The ventral vascular bundles occur in between two carpels. Group 3. Cornus, Toricellia, Bothrocaryum, Dendrobenthamia, Swida, Chamaepericlymenum and Aucuba: Fruits are drupe or aggregate drupes without obvious ribs and having unicellular trichomes.The fruits of Cornaceae and Araliaceae dif fer in structure. In the former, the oil tubes are absent in the mesocarp, endocarp is composed of stone cells and fibers, and ventral vascular bundles are absent. All those characteristics of the family do not appear in Araliaceae and therefore fruit structures support to seperate Cornaceae from Apiales. The Helwingia has fruit characteristics which differ from the other groups of Cornaceae and provide the evidence for the genus shoul d be an independent family. Some fruit characteristics of Cornus sensu lato are unique, which do not oc cur in the other groups, such as the lignified cells appear in the mesocarp of Bothrocaryum; the pericarp of Chamaepericlymenum has no tannin; the oute r tangential walls of epicarp cells of Dendrobenthamia are bulging and with tannin; The endocarp of Cornus has secretory cells. The fruit anatom y supports that all those taxa could not be placed in the Cornus sensu lato. The fruits and s eeds structures of Toricellia and Aucuba support that both taxa could be sepereate from Cornus sensu lato.The study improve the m orphological study of Cornaceae and some taxa of Araliaceae, provide the m orphological evidence for th e classical taxonom y and molecular systematics, show that the fruit structure have important singnificance for the systematics study of the family, and also provide the morphological basis for the further study of molecular systematics of Cornaceae.