Chromosome numbers of sect. Macrolespedeza have been reported by several workers. Kawakami (1930) reported the haploid number to be nine in L. bicolor, L. cyrtobotrya, L. homoloba, L. Sieboldii (=L. Thunbergii), and L. Sieboldii var. albifiora (=L. japonica). Cooper (1936) examined the chromosome numbers of the species of sect. Lespedeza and reported the diploid number to be 18 in L. variegata and L. sericea, 20 in L. tomentosa, and 36 in L. daurica. He suggested that nine is probably the basic number for the genus Lespedeza. Pierce (1939) reported the somatic chromosome number to be 22 in L. bicolor, L. cyrtobotrya, and L. cyrtobotrya var. pedunculata, L. Maximowiczii (non Schneid.) (=L. bicolor), L. Thunbergii, L. japonica var. intermedia, L. robusta, L. floribunda, and L. virgata, n=9 in L. sericea, 2n=20 in L. violacea, L. Stuvei, L. repens, L. capitata, L. variegata, L. Izirta, L. pilosa, L. procumbens, L. frutescens, etc. He suggested that the basic chromosome number for the American species of Lespedeza is 10, and that for other species the basic number is 11 although n=9 has been reported for certain Japanese species. Young (1940) reported n=9, 10, and 2n=20 in American species, n=11 in L. Thunbergii, and 2n=22 in L, Uyekii. Lee (1969) reported 2n=20 in L. bicolor var. typica, L. cuneata, 2n=40 in L. juncea var. inschanica, and 2n=22 in L. Uyekii. Clewell (1971) reported n=11 in L. bicolor, L. cyrtobotrya, L. homoloba, and L. Thunbergii, and 2n=20, n=10, and 2n=22 in L. cuneata. Kondo et al. (1977) examined intraspecific variation of karyotypes in Lespedeza and Desmodium and reported 2n=22 in L. cyrtobotrya and 2n=20 in L. cuneata and L. pilosa. They reported intraspecific variation of karyotypes in L. cyrtobotrya with five karyotypes. They pointed out that Lespedeza and Desmodium had fewer differences thansystematictreatments had previously suggested, although the chromosome number of the species of both genera seemed to be divided into two groups, one with 2n=20 and the other with 2n=22.

In the present study the chromosome numbers of the following species were examined: L. bicolor, L. Buergeri, L. cyrtobotrya, L. formosa subsp. velutina, L. homoloba, L. patens, and L. Thunbergii. Chromosome numbers were counted in root tips using the squashing method. Root tips were obtained from plants cultivated in the Botanical Gardens, the University of Tokyo, pretreated with 0.002M 8-hydroxyquinolinc aqueous solution for 4 hours at room temperature, and fixed with Farmer's solution ethyl alcohol: glacial acetic acid=3: 1) for more than 1 hour. Root tips were stained (absolute with 5% aceto-orcein solution in IN hydrochloric acid and then squashed. Our results suggest that the basic number for sect. Macrolespedeza is not 9 but 11 (Table 28). Although polyploidy is not reported in sect. Macrolespedesza, Murata (1978) suggested the possibility for polyploidy of L. patens. According to our observations L. patens has the somatic number 2n=22 like other species of sect. Macrolespedesza; no polyploidy was observed. The lack of polyploidy and chromosome diversification is one reason why hybridization occurs frequently in sect. Macrolespedesa. The chro mosome number 2n=22 occurs not only in sect. Macrolespedeza and sect. Lespedeza, but also in the genera Campylotropts, Kwnmerowia, and Desmodium.