J Syst Evol ›› 2010, Vol. 48 ›› Issue (5): 344-349.DOI: 10.1111/j.1759-6831.2010.00094.x

• Research Articles • Previous Articles     Next Articles

Morphology, distribution and chromosome counts of two varieties of Hedychium villosum (Zingiberaceae)

1, 2Fei YU 1, 3W. John KRESS 1Jiang-Yun GAO*   

  1. 1(Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, the Chinese Academy of Sciences, Mengla, Yunnan 666303, China)
    2(Graduate School of the Chinese Academy of Sciences, Beijing 100049, China)
    3(Department of Botany, MRC-166, National Museum of Natural History, P.O. Box 37012, Smithsonian Institution, Washington DC 20013-7012, USA)
  • Received:2010-01-12 Published:2010-09-26

Abstract: Polyploidy is a major mechanism of adaptation and speciation in plants. Two varieties of Hedychium villosum, var. villosum and var. tenuiflorum, primarily differ in plant and flower size. Chromosome number suggests that var. tenuiflorum is diploid (2n=34) and var. villosum is tetraploid (2n=68). Although the flowers of the two varieties do not have any difference in floral shape, each can be easily distinguished morphologically because the shoots, leaves and flowers of the tetraploid var. villosum are consistently larger than the diploid var. tenuiflorum. The two varieties each possess distinct geographic ranges and habitats, and no sympatric distribution has been found. The tetraploid var. villosum has a broader geographic distribution range and more diverse ecological habitats than the diploid var. tenuiflorum. The two varieties are also completely reproductively isolated due to the non-overlap of the their flowering times. The two varieties should be recognized as two distinct species as they fulfill the requirements of various species concepts. Thus, we suggested that the tetraploid var. villosum should be kept as Hedychium villosum and the diploid var. tenuiflorum should be renewed to Hedychium tenuiflorum.

Key words: polyploidy, morphology, distribution, Hedychium villosum, Zingiberaceae.