Non-lexicalist theories assume a tight relationship between functional structure and exponence. A different view informs the analysis proposed in this paper. While the non-lexicalist view is endorsed, it is argued that morphemes have a life of their own and do not consistently and faithfully reflect functional architecture. Perfective Inflection in Moroccan Arabic with its standard, but nevertheless challenging restrictions on the way Number and Gender are allowed to combine is taken as a case in point. The discussion is preceded by a detailed study of the vowel system of the language and selected aspects of its templatic structure.