Plant Diversity ›› 2013, Vol. 35 ›› Issue (3): 393-400.doi: 10.7677/ynzwyj201313042

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A New QinghaiTibet Plateau Endemic Genus Sinoswertia and Its Pollination Mode

 HE  Ting-Nong-1, LIU  Shang-Wu-1, LIU  Jian-Quan-1、2   

  1. 1 Key Laboratory of Evolution and Adaptation of Plateau Biology, Northwest Plateau Institute of Biology, Chinese Academy
    of Sciences, Xining  810001, China; 2 State Key Laboratory of Grassland AgroEcosystem, College of
    Life Science, Lanzhou University, Lanzhou 730000, China
  • Online:2013-05-25 Published:2013-07-26
  • Supported by:

    Key Project of the National Basic Research Program of China (2007FY110100)

Abstract:

Available data from both embryological and molecular studies of the monotypic section Heteranthos within the genus Swertia s.l. suggested that this taxon should be erected as a separate genus. We examined morphological variations of the only species across multiple populations and found that it has two types of individuals and one type contains both large and small flowers while the other only small flowers. However, all small and most large flowers set seeds through a cleistogamous pollination mode, which may have evolved in response to the reproductive adaptation to the arid habitats of the QinghaiTibet Plateau. However, this pollination mode is different from the outcrossing breeding system observed for the other Swertia species. Dimorphic plants and flowers distinguish this species from the other Swertia species and related genera. We further discussed the systematic position of this species based on the comprehensive data and the current data support its close relationship with Halenia. The morphological distinctness and systematic position of this species from all comparisons justified its generic status. We here place this species in a new genus Sinoswertia, and describe and illustrate it. However, after excluding this species, Swertia s.l. is still polyphyletic based on the molecular evidence. The taxonomic treatment of this polyphyletic genus possibly due to the recent radiative diversification and convergent evolution poses an extreme challenge at the present and pends further detailed studies.

Key words: Sinoswertia, Dimorphic individuals, Dimorphic flowers, Pollination mode

CLC Number: 

  • Q 949