Comparative chromosomal features for four Apocynaceae species from Northeastern Thailand

The comparative chromosomal features of four species belonging to family Apocynaceae from Northeastern Thailand were studied the root tips. somatic chromosome numbers all specimens found be 2n = 36 for Allamanda blanchetii, 18 A. cathartica, 20 in schottii and 52 Cryptostegia grandiflora. cathartica have same number previous except C. grandiflora differs previously reported. Moreover, has never been previously. karyotype formulas are presented as 12 m + 4sm 2st 10 8sm schottii. both strains differ those Therefore, karyotypes two species, schottii, different it can used classification. This study including (Apocynaceae) is first reported Thailand.