Karyotype analysis of six species of the genus Ophiopogon (Convallariaceae - Ophiopogoneae)

Ophiopogon brevipes from Doi Suthep, Chiang Mai Prov., Thailand, O. jaburan from Isls. Koshikijima and Isl. Kuroshima, Kagoshima Pref., Japan, O. planiscapus from Mt. Sanjohgatake, Nara Pref., Japan, and O. siamensis from Doi Inthanon, Chiang Mai Prov., Thailand were found to be diploid with 2n = 36, O. sylvicola from Mt. Wawushan, Sichuan, China to be triploid with 2n = 54, O. japonicus var. japonicus from Minoo, Osaka Pref., Japan to be hypotetraploid with 2n = 70, and O. japonicus var. umbrosus from Yao, Osaka Pref., Japan to be tetraploid with 2n = 72. O. brevipes, O. siamensis and O. sylvicola were karyologically investigated for the first time in the present study. The chromosome number 2n = 54 and 2n = 70 are new counts for the genus. The karyotypes analyzed in the present study are categorized into two groups: Jaburan-group with two pairs of medium-sized chromosomes and Brevipes-group with three pairs of medium-sized chromosomes, although the karyotypes of O. japonicus are categorized into neither group. O. jaburan, O. planiscapus, O. siamensis and O. sylvicola with karyotypes of the Jaburan-group, are distributed in warm temperate to cool temperate zones. O. brevipes with a karyotype of the Brevipes-group, is distributed in a tropical monsoon zone.