Abstract: In this paper, it is suggested that we consider "evolutio-nary degree" in dertermining whether "difference between spe-cies" or "variation within species". It is emphasized that these species, which have high evolutionary degree and distribute widely, usually are polymorphic species, hence may be sepa-rated into subspecies. On the contrary, those species, which have low evolutionary degree and distribute strictly, usually are good individual species. Accordingly, this part of the pa-per has discussed following taxa:(1) Fraxinus huangshanensis S. S. Sun, sp. nov. It is a primitive species and distribute stritly. It has been compared with some related species by the aid of statistical methods and coordinative diagrams. (2) Fraxinus floribunda Wall. ssp. insularis (Hemsl.) S. S.Sun, comb. nov. It is a variable species, which widely distributes in the south China and has ever been regarded as F. relusa Champ.It is here considered as a geographical race of F. floribunda Wall. (3) Fraxinus longicuspis S. Z. The species, type from Japan, is a common Ash in the south-eastern China, but has wrongly determined before. Ac-cording to the original description and a lot of available in-formation, it is, in fact, a new record species in China, even if there are a few differences between that in China and in Japan. (4) Fraxinus nigra Marsh. ssp. mardshurica (Rupr.) S. S-Sun, comb. nov. The species, which was determined as F. mandshurica Rupr., is much closely relative to Fraxinus nigra Marsh., na-tive in North America. According to the identities of the cha-racters and the habitats, We consider it as a geographical subspecies of Fraxinus nigra Marsh.