爪塩 is an unusual Kanji. The first character, usually taken as nail or claw, may also refer to "tip". This makes more sense, as we can translate as "Salty Tip", referring either to twigs or leaf tips. Perhaps a speckled, whitish variegation of the leaf tip? Further, Nakajima does not specify the species, and some Section Macrantha (Snakebark) species exhibit a glaucus bloom on new twigs, which could support the interpretation. As this maple seems to have disappeared from trade, it may remain forever enigmatic. Note also that Nakajima misspells the rōmaji "tsumma", so it is possible there is a mis-transcription somewhere. (ED)