Abstract: This paper analysed the karyotype of 15 species of Aigeiros in Populus. The resultswere as follows: P. nigra var. thevestina, 2n = 38 = 3M + 29m + 5sm + 1st; P. del. cv. ×Lux ×P. ×canadensis cv. Shanhaiguanensis, 2n =38 =2M +27m +4sm +5st (4SAT) ; P. ×euramericana cv. ‘74 /76’, 2n = 38 = 1M+29m (1SAT ) +5sm +3st (3SAT) ; P. euramericana CL 13, 2n = 38 = 3M + 23m + 6sm + 3st (1SAT ) + 3t (3SAT) ; P. ×canadensis Moench, 2n =38 =1M +27m +6sm +4st (4SAT) ; P. maximowiczii Henry ×P. deltoids Bartr. , 2n = 38 = 1M + 24m + 9sm ( 2SAT ) + 4st; P. Zhongshangnensis, 2n = 38 = 4M + 27m (1SAT) +2sm +3st (2SAT ) +2t; P. ×beijingensis, 2n =38 =3M +28m +3sm +4st (2SAT) ; P. ×Liaoningensis, 2n =38 =1M +27m +3sm +6st (1SAT ) +1t (1SAT) ; P. CL ‘Langfang 1’, 2n =38 =3M +28m +3sm +4st (2SAT) ; P. ×gaixianesis, 2n =38 =2M +27m +4sm (1SAT ) +4st (3SAT) + 1t; P. deltoids CL 2 (GMO) , 2n =38 =26m +7sm (2SAT ) +4st (1SAT ) +1t (1SAT) ; P. ×Qungainensis - 3, 2n = 38 = 1M +27m + 8st ( 2SAT) + 2t (2SAT) ; P.×Zhongjinnensis 2, 2n = 38 = 1M + 18m + 13sm ( 1SAT ) + 5st (2SAT) +1t (1SAT) ; P. ×eur. cv. San Martino ×P. canadensis cv. Shanhaiguanensis 2n =38 =2M +26m +6sm +4st. The karyotypes of Aigeiros were all of 2B type. The karyotype differences mainly lay in the numbers of metacentric chromosomes (25 - 32) and telomeric chromosomes (1 - 6). The karyotype data provided reference for species (or varieties) characterization of Aigeiros.

Key words: Populus, Aigeiros, Karyotype analysis