[4] A finding that property is separate or community in character, even though the title apparently stands in joint tenancy is binding and conclusive upon an appellate court if it is supported by substantial evidence. [5, 6] This principle applies to the presumption of joint tenancy created by the form of deed or account and to the presumption of community property created by Civil Code section 164. (Benom v. Benom, 173 Cal. App. 2d 286, 297 [343 P.2d 638].) In the case of Thomasset v. Thomasset, 122 Cal. App. 2d 116, 123 [264 P.2d 626], it is said: