Abstract: The pollen morphology of Spiraeoideae(Rosaceae) includeing the genera,Sibiraea,Aruncus,Sorbaria,Physocarpus,Neillia and Stephanandra in CHina was reported in this paper.All the pollen grains are tricolporate,the shapes are subspheroidal.The pollen grains are small,the smallest one was observed in Spiraea purpurea with the size of 14.87(12.75-16.58)um×15.17(12.75-17.4)um,while the biggest on was observed in Physocarpus amurensis with the size of 27.97(19.89-38.25)um×30.91(26.77-33.66)um.Amb is 3-lobed circular in common but syncolpolate was observed in Physocarpus amurensis.The colpi are usually long but narrowed in two ends.The ora form rectangle.Sculptural types of the subfamily Spiraeoideae include foveolate,striate-foveolate,striate-reticulate,and striate.All the sculptural types in Rosaceae were observed except spinulate type.The foveolate may be the most primitive pollen sculpture in Rosaceae,while the types of striate and striate-reticulate are more advanced.The pollen sculpture is either striate-reticulate or striate in the genus Spiraea without foveolate,which shows that the degree of differentiation is rather high in Spiraea.The pollen morphology supports the arrangement of tribes and genera in subfamily Spiraeoideae given by A. Takhtajan in 1997.

Key words: Rosaceae, Spiraeoideae, Pollen morphology