Abstract
The species of Trachelospermum (Apocynaceae) are evergreen, woody lianas widely distributed in Japan. Morphologically intermediate plants between T. asiaticum and T. jasminoides have been observed. We conducted morphological and genetic investigations to clarify the possibility of hybridization events between T. asiaticum and T. jasminoides. Analysis of floral and vegetative characters of living and herbarium specimens indicated that morphologically intermediate plants frequently and widely grow in overlapping distribution areas. The results of sequencing and PCR-RFLP analyses partly confirmed natural hybridization between the two species and detected suspected hybrids among samples morphologically identical to T. jasminoides.
