Abstract
Somatic chromosome numbers were examined for 28 species and two varieties of seven genera in Asclepiadaceae collected in Japan. The chromosome numbers of 21 species and two varieties were newly reported here. All taxa examined had chromosome numbers of 2n=22 except for 2n-44 in Cynanchum caudatum var. caudatum, Vincetoxicum ambiguum, V. sublanceolatum var. sublanceolatum, V. sublanceolatum var. macranthum and 2n=24 for Cynanchum boudieri. In Cynanchum caudatum, chromosome number of 2n=22 was also found as well as 2n=44, indicating that intraspecific polyploidy exists in the species.
