Delaware has enacted a business trust law that governs both domestic and foreign trusts.  12 Del. Code § 3801 et seq.  California has no similar law but it does purport to impose certain provisions of its General Corporation Law on business trusts. 

Business trusts are brought within the ambit of the GCL by virtue of Corporations Code Sections 170 and 171.  The former defines "foreign association" as a business association recognized as a trust under the laws of a foreign jurisdiction.  The latter defines "foreign corporation" to include (unless otherwise stated) foreign associations when used in Section 191 (defining "transact intrastate business"); Section 201 (governing the use of "bank", "trust" and "trustee" in names); Section 2203 (unauthorized transaction of intrastate business); Sections 2258-59 (criminal penalties); and Chapter 21 (governing foreign corporations).  Notably, however, Section 2115, California's pseudo-foreign corporation statute, does not apply to a foreign association.