The Mandan form occurs in maʔpéʔ ósere, which may derive from wa- ‘absolutive’ + ąp ‘day, dawn’ + ó- ‘nominalizer’ + sre ‘to bloom’, meaning ‘dawn flower’. The word is unusual, in that it has third-mora accent. The Hidatsa formation is similar: wa•p- ‘day’ plus -ha• ‘plant’ (compare Hidatsa wa•cu ‘cherry’, wa•cua• ‘cherry tree’). The sunflower is attested archaeologically all up and down the eastern plains as a common food source. There is strong evidence that it was domesticated fairly early. The fact that there do not appear to be cognates in most of the languages may suggest further refinement in our chronologies for subgroup development and/or may point to development outside the plains area. However, cf. ‘chinquapin, lotus, cattail’.