成唯識論述記 4.207

4.207

述曰：此色、不相應，不可說為內種依止；離識無實性故；如龜毛等。色體即心故，唯應心為諸種依止；不相應假依心而立，亦應實法為種子依。前已數遮故不為量，但可言異。

The Commentary states: These—form and unassociated [formations]—cannot be spoken of as the support for internal seeds; because apart from consciousness they have no real nature; like a turtle's hair and so forth. Since the substance of form is just citta, citta alone should be the support for all seeds; unassociated [formations] are designations established in dependence on citta, so real dharmas should also serve as the support for seeds. Since they were repeatedly refuted before, no inference is constructed here, but one need only state they are different.