jats:p Standard accounts of HPSG assume a distinction between morphology and syntax. However, despite decades of research, no cross-linguistically valid definition of 'word' has emerged (Haspelmath, 2010), suggesting that no sharp distinction is justified. Under such a view, the basic units are morphemes, rather than words, but it has been argued this raises problems when analysing phenomena such as zero inflection, syncretism, stem alternations, and extended exponence. We argue that with existing HPSG machinery, a morpheme-based approach can in fact deal with such issues. To illustrate this, we consider Slovene nominal declension and Georgian verb agreement, which have both been used to argue against constructive morpheme-based approaches. We overcome these concerns through use of a type hierarchy, and give a morpheme-based analysis which is simpler than the alternatives. Furthermore, we can recast notions from Word-and-Paradigm morphology, such as 'rule of referral' and 'stem space', in our framework. We conclude that using HPSG as a unified morphosyntactic theory is not only feasible, but also yields fruitful insights.</jats:p>