I already treated the species count of Japanese maples as 26 species, and here I should like to describe them more precisely up to the level species, subspecies, variety and form. The following description is almost all based on document No 4 "Maples of the World" and document No 3 by Prof.Ogata(1965).
1. In "Maples of the World", more than 30 kinds of Japanese maples are described including up to species and subspecies.
2. According to a view by Prof.Ogata's thesis(1965) , 23 species are found with some varieties.
as varieties of Acer mono : Those "may be considered respectively even as independent species."
var.glabrum(ezo-itaya), var.marmoratum(enko-kaede), var.taishakuense(taishaku-itaya), var.glaucum(urajiro-itaya), var.mayrii(aka-itaya), var.trichobasis(itomaki-itaya) and var.ambiguum(oni-itaya)
as varieties of Acer miyabei : var.miyabei and var.shibatai (shibata-kaede)
as varieties of Acer amoenum : var.amoenum and var.nambuanum (nanbu-koha-momiji)
as varieties of Acer capillipes : var.capillipes and var.morifolium (yakushima-onaga-kaede)
as varieties of Acer tschonoskii : var.tschonoskii and var.australe (nangoku-minekaede)Then, the count of species up to varieties might be regarded as 34. (Acer buergerianum and Acer oblongum are not included.)
In Thesis by Prof.Ogata(1965), we can see up to 46-50 forms in number.
When Acer buergerianum and Acer oblongum are added and var.formosanum (taiwan-to-kaede) as a variety of Acer buergerianum and var.macrophyllum (oba-minekaede) as a variety of Acer tschonoskii are moreover added, the count might be regarded as 50-54.
I think that the count of species will depends upon how wide domain should be set up or how classification should be done. Here, I referred to the questions how to recognize, degree of precision, viewpoint, etc. I hope young students would be interested in a process from the present analysis to a characteristic approach by themselves.