The Flowering Phenology of Four Species of Calligonum (Polygonaceae) and its Evolutionary Significance

The Flowering Phenology of Four Species of Calligonum (Polygonaceae) and its Evolutionary Significance.

The flowering phenologies of four sympatric species of Calligonum L. were studied during three consecutive years at five levels (population, individual, branch, branchlet, single flower) in eastern Xinjiang. The main observations included (1) The flowering pattern of C.calliphysa is similar to C. rubicundum, while C.densum is similar to C.ebinuricum at the level of population, individual and branch; the former two are called as “Mass-flowering pattern”, the latter two are termed as “Extended-flowering pattern”. (2) According to the characters of flowering, we argue that the relationship between C.calliphysa and C.rubicundum is close, while C.densum is close to C.ebinuricum. And the order of flowering also reflects this relationship and evolutionary trends. (3) The four species flowering duration were overlapped, and the natural distribution regions were overlapped partly, these made hybridization possibly. .