Chromosome studies of Taraxacum denudatum and T. pectinatum in Japan

We report on the occurrence of karyotypes of two species and one variety of dandelion, Taraxacum denudatum var. denudatum, var. arakii, and T. pectinatum, in western Japan. The two varieties of T. denudatum had two polyploid numbers of 2n=32 (4x) and 40 (5x). In T. denudatum var. denudatum, the tetraploid plants had a karyotype form expressed as 2n=32=3M+25m+2m^cs+1sm+1sm_cs, and the pentaploid plants comprised two karyotype forms of 2n=40=2M+32m+2m_cs+3sm+1sm_cs and 2n=40=5M+32m+3m_cs. In T. denudatum var. arakii, the tetraploids had a karyotype form expressed as 2n=32=27m+5m_cs and the pentaploids had a karyotype form of 2n=40=3M+33m+3m_cs. Taraxacum pectinatum was a tetraploid dandelion with a karyotype expressed as 2n=32=23m+5m_cs+2sm+2sm_cs. The present study by their karyotype analyses suggests that T. denudatum var. denudatum, T. denudatum var. arakii, and T. pectinatum are all allopolyploid dandelions.