 For instance, the Omaha had a patrilineal system, and considered mixed-race children of European or "white" fathers to be white unless formally adopted into the tribe by a man.Other tribes had matrilineal systems, and children were considered born into the mother's clan and took their status from her.Due to hypodescent (assignment of children of a mixed union to the subordinate group) and the fact that many of the mixed-race children grew up in tribes on the frontier, Europeans tended to classify them as being more Indian than white.