A systematic study of Rosa sericea (Rosaceae) complex: Are R. omeiensis and R. sericea conspecific?

Abstract

The Rosa sericea complex contains R. omeiensis, R. sericea and R. mairei. They are morphologically similar to one another and the systematic status of R. omeiensis has been controversial. In this study we examined ca. 2000 herbarium specimens of the three taxa in major herbaria in China and conducted field observations in Sichuan and Yunnan. We also performed SEM study of pollen morphology and seed coat structure. We further carried out intensive morphometric study on the leaflet, pollen, and seed morphology. Our results showed that R. mairei can safely be distinguished from other two, while there are no obvious discontinuities in pollen morphology, seed coat structure and plant morphology in general for R. omeiensis and R. sericea. Nevertheless, in most cases R. omeiensis and R. sericea can be distinguished from each other to some extent. They also have different geographical distributions. Therefore we here sink R. omeiensis to be a variety of R. sericea. Six forms related with these two taxa are synonymized. The four synonyms of R. sericea var. sericea include R. omeiensis f. glandulosa T. T. Yu & T. C. Ku, R. omeiensis f. pteracantha Rehder & E. H. Wilson, R. sericea f. glabrescens Franchet, and R. sericea f. pteracantha Franchet, while two synonyms of R. sericea var. omeiensis include R. omeiensis f. paucijuga T. T. Yu & T. C. Ku and R. sericea f. glandulosa T. T. Yu & T. C. Ku. Detailed morphological descriptions and geographical distributions of the three taxa are given.