A patch, grouping or zone of plants evident in overall plant cover, which appears distinct from other such units because of the vegetation's structure and floristic composition; a given unit is typically topographically distinct and typically has a rather uniform soil, except possibly for relatively dry microsites (e.g., tree bases, old tree stumps, mosquito ditch spoil piles and small earth hummocks) in an otherwise wet area or relatively wet microsites (e.g. small depressions) in an otherwise dry area.