This paper reports a hybridization experi ment, where a baseline ML dependency pars er, LingPars, was allowed access to Con straint Grammar analyses provided by a rule based parser (EngGram) for the same data. Descriptive compatibility issues and their in fluence on performance are discussed. The hybrid system performed considerably better than its ML baseline, and proved more ro bust than the latter in the domain adaptation task, where it was the bestscoring system in the open class for the chemical test data, and the best overall system for the CHILDES test data.