Abstract: Intact seeds of Cynanchum otophyllum were innately dormant at maturity in November. Seeds planted in a nonheated greenhouse in November germinated the following spring and most of the germination occurred between 28 March -4 April , when the mean maximum and minimum daily temperatures were 19.0 and 9.9℃, respectively. Stratification was effective in overcoming dormancy , and nondormant seeds germinated in both light and darkness . About one week of stratification was effective in overcoming dormancy in some of the seeds; seeds stratified in light for 1 week and then incubated in darkness at 25/15℃ germinated to 75. 4%. Seeds stratified in light or darkness for 2 and 3 weeks and then incubated in light or darkness germinated to 66.4% or more at thermoperiods of 30/20 and 25/15℃ but germinated to 20.1% or less at 20/10℃ . Seeds stratified for 6 weeks also germinated to high percentages (65.3% or more ) at 20/10℃.

Key words: Cynanchum otophyllum