Abstract: Two species of Talinum crassifolium (Jacq.) Gaertn. were used in this experiment, morphological structure and karyotype differences between the two species of T. crassifolium(Jacq.) Gaertn. were observed and analyzed by paraffin sectioning combined with fluorescence microscopy and root tip squash method,it provided theoretical reference for the identification of T. crassifolium (Jacq.) Gaertn. The results indicated that plant height, stem diameter, leaf thickness, leaf area and flower diameter in species 2 were significantly greater than those in species 1, but there was no significant differences in flower color and thousand kernel weight between the two species. In microstructure, the number of stomata per unit area in upper epidermis of species 1 was significantly less than that of species 2, while the number of stomata per unit area in lower epidermis was significantly greater than that of species 2; The style morphology of the two species of T. crassifolium (Jacq.) Gaertn. were both three-petal feather; The stem cross section of species 1 was nearly round, and that of species 2 was irregular. In species 1, the chromosome number was 2n=2x=40, the karyotype formula was 2n=2x=38m+2M, the relative length of chromosomes was 8L+14M₂+12M₁+6S, the karyotype category belonged to type 1B, the coefficient of karyotype asymmetry was 54.50%; In species 2, the chromosome number was 2n=2x=24, the karyotype formula was 2n=2x=18m+6sm, the relative length of chromosomes was 6L+4M₂+8M₁+6S, the karyotype category belonged to type 2B, the coefficient of karyotype asymmetry was 59.37%. The number of stomata per unit area of upper and lower epidermis, stem cross section shape and karyotype of two species were significantly different, it could be used as reference indexes to identify T. crassifolium (Jacq.) Gaertn. species.

Key words: Talinum crassifolium(Jacq.) Gaertn., morphological comparison, microstructure, anatomical structure, karyotype