Representation of syntactic relations by dependency trees with nodes labelled by categories of lexical morphemes and with branches effectively labelled by relational morphemes reveals the relationships of elements to which selectional restrictions apply more directly than do current phrase structure characterizations and avoids certain defects of a configurational definition of relationships. The relations are those of case as defined by Fillmore and more generally those of head-of and complement-of. Adoption of the view that subject-of is a surface rather than a deep structure relation eliminates the need to distinguish strict subcategorization rules from selectional rules. © 1970, Cambridge University Press. All rights reserved.