1. Comparative morphological studies of a group of Uromyces on the following 13 Japanese species of Lespedeza and one of Microlespedeza, which has been treated as a collective species, Uromyces Lespedezae-procumbentis (SCHW.) CURTIS, have been conducted. They are: Lespedeza bicolor TURCZ. (& var. japonica NAKAI), L. Buergeri MIQ., L. cuneata G. DON., L. cyrtobotrya MIQ., L. cystoides NAKAI var. inschanica NAKAI, L. homoloba NAKAI, L. Maximowiczii C. K. SCHN., L. nipponica NAKAI, L. pilosa SIEB. et ZUCC., L. pubescens HAYATA, L. retusa NAKAI, L. Thunbergii NAKAI, L. tomentosa SIEB. and Microlespedeza striata MAK. From the results of the studies, the fungi on those different plants were divided morphologically into the following two distinct species.1) Uromyces Lespedezae procumbentis (SCHW.) CURTIS on the above 13 species of Lespedeza. Among these host plants, the following 7 species; Lespedeza cystoides var. inschanica, L. homoloba, L. Maximowiczii, L. nipponica, L. retusa, L. Thunbergii and L. tomentosa are new additions to the hosts of the present species.2) Uromyces Itoanus HIRATSUKA, f. (nov. spec.) on Microlespedeza striata MAK. This fungus also occurs on Microlespedeza stipulacea MAK. in Manchuria.2. In order to determine the parasitism of Uromyces Lespedezae-procumbentis (SCHW.) CURTIS and U. Itoanus HIRATSUKA, f., inoculation experiments were undertaken, and the results of the experiments are summarized as follows:-1) A number of inoculation experiments with aecidiospores or uredospores of Uromyces Lespedezae-procumbentis on Lespedeza bicolor var. japonica and L. Buergeri were made on Lespedeza bicolor, L. bicolor var. japonica, L. Buergeri, L. cuneata, L. pilosa, L. Thunbergii, L. virgata and Microlespedeza striata, and positive results were obtained on Lespedeza; L. bicolor, L. bicolor var. japonica, L. Buergeri and L. Thunbergii.2) A number of inoculation experiments with uredospores of Uromyces Itoanus on Microlespedeza striata were made on Lespedeza bicolor, L. bicolor var. japonica, L. Buergeri, L. cuneata, L. pilosa, L. Thunbergii, L. virgata Microlespedeza striata, and positive results were secured on the controlling plant, Microlespedeza striata, while on all species of Lespedeza inoculations were unsuccessful.