A dichotomous key is a tool that allows the user to determine the identity of items in the natural world, such as trees, wildflowers, mammals, reptiles, rocks, and fish.
Keys consist of a series of choices that lead the user to the correct name of a given item.
Therefore dichotomous keys always give two choices in each step. This Key to Trees is presented by the Department of Food and Resource Economics and the Department of Plant and Soil Sciences in the College of Agricultural Sciences at the University of Delaware. The history of plant nomenclature. The names of plants. The correct form of plant names.