Daco-Romance dialects inherited the effects of two distinct sound changes which coincidentally gave rise to almost identical distributional patterns of alternation in the inflectional paradigm of the verb. Once the original phonological conditioning of the alternants (apparently) ceased to operate, what was left was a frequently encountered yet ‘nonsensical’ pattern of paradigmatic distribution, irreducible to any coherent common set of morphosyntactic features. It appears to have been, in the terminology of Aronoff, ‘morphomic’. Drawing on a large body of historical and comparative dialectological data, I chart the history of this apparently morphomic pattern. For much of the history of Daco-Romance, it constitutes a kind of leitmotiv of paradigmatic organisation, practically inviolable in its distribution and providing a recurrent distributional model for novel types of alternation, unconnected with the original sound change. Yet, in relatively recent times, the distributional coherence has collapsed in apparent chaos. My analysis of these diachronic facts will suggest that there are morphological phenomena which may properly be seen as morphomic while also retaining elements of extramorphological, phonological conditioning.