AbstractFifteen Asiatic and four North American taxa of the genusDisporum(Liliaceae‐Polygonateae) were karyologically examined. The chromosome numbers and karyotypes ofD. multiflorum(2n= 14),D. sessilevar.sessilef.minus(2n= 16),D. sessilevar.micranthum(2n= 16), andD. taipingense(2n= 16) were determined for the first time. Thirteen additional chromosome counts and karyotype analyses were made for the following 11 AsiaticDisporumtaxa (SectionDisporum):D. calcaratum(2n= 14 and 16‐a new count),D. cantoniense(2n= 14 and 16),D. kawakamii(2n= 16),D. longistylum(2n= 16),D. lutescens(2n= 16),D. sessilevar.sessilef.sessile(2n= 16),D. shimadai(2n= 14),D. smilacinumvar.smilacinum(2n= 16),D. smilacinumvar.ramosum(2n= 16),D. uniflorum(2n= 16), andD. viridescens(2n= 16 + 1B‐a new count).The karyotypes of four North American taxa (SectionProsartes) were reported for the first time, although the same chromosome counts had been previously known for each taxon:D. hookeri(2n= 18),D. lanuginosum(2n= 18),D. maculatum(2n= 12), andD. smithii(2n= 16).D. maculatumpossesses a very characteristic satellite on the long arm of the fifth subterminal chromosome; the karyotype ofD. smithii(x= 8) is also characterized by possessing a minute satellite on the short arm of the fifth pair and also by a secondary constriction on the short arm of the sixth pair.One of the most noteworthy findings made in the present study is that the species of SectionDisporumand SectionProsartespossess conspicuously distinct cytological features in the size of resting nuclei and cells, interphase chromosomes, and mitotic prophase and metaphase chromosomes. The plants of SectionDisporumhave distinctly larger resting nuclei and cells than those of SectionProsartes; SectionDisporumpossesses a typical homogeneously diffused type (= densely diffuse type according to Tanaka, 1977) of interphase chromosomes, while SectionProsarteshas a prochromosome type; the condensation pattern of their prophase chromosomes is of a continuous type in SectionDisporum, while a proximal type occurs in SectionProsartes; SectionDisporumpossesses distinctly larger sized metaphase chromosomes, as compared with SectionProsartes. All of these karyological differences described above strongly support D. Don's original concept (1839, 1841) of treatingDisporumandProsartesas two separate g