Tree

Traditionally, plant taxonomists have relied upon the morphology of plants' reproductive structures to determine their evolutionary relationships. More recently, they have also used biochemical characteristics, DNA sequences, and additional features. Occasionally, there are disagreements about the relationships of different plant species. These disagreements are important in stimulating further research.

In identifying a tree in nature, dendrologists do not always rely upon its reproductive structures, because these are often only available for a brief time of the year. In practice, they typically rely upon features of a tree's leaves, twigs, bark, wood, habit (general shape and appearance), and habitat as clues for identification.