In 1994 to 1995, available spores were obtained from the following 11 localities : three localities in Taiwan, one in India, three in Indonesia, one in New Guinea, one in Hawaii of USA,and each one in Surinum and Guiana in South America. Spores from these localitiesand those from Okinawa Prefecture and Chiba Prefecture, which were selected as the representatives of the south type and the north type of C.thalictroides, respectively, were sown onto agar media to yield gametophytes. Developed gametophytes were conducted to undergo self-fertilization within each source and crossing between two Japanese sources and eleven foreign sources. Electrophoretic analyzes on PGI and PGM allozymes were carried out for sporophyte progeny. Sporophyte progeny of 196 offsprings were obtained through crossing treatment. Out of these, 60 offsprings were impossible to be judged as selfed ones or hybrids, because parental sporophytes had the same allozymes as the north type and the south type. Allozyme analyzes revealed that, of remaining 136 offsprings, 74 were of selfed origin and 62 were of hybrid origin. Spores of hybrid sporophytes were sown onto agar media. The degree of the germination rate of spores indicated that one spore source in Indonesia was of the north type and the other two were probably of the south type. It was also indicated that all the three spore sources of Taiwan were of the north type and the spore source of Guiana of South America was probably of the south type. Whether the remaining hybrids are of the north type or the south type will be checked soon after they will produce spores. The present study suggests that there are at least two cross-sterile groups in C.thalictroides in the world.