The major tree genera are listed below by taxonomic family.
For classification of flowering plants, see APG II system.
About 210 eudicot families include trees. [1] [2]
About 10 Monocotyledon families include trees. [1] [2]
17 magnoliid families include trees. [1] [2]
7 families, all of which include trees. [3]
Only one species.
Both families of cycads include trees. [3]
Tree ferns are not true trees - their "trunks" are not composed of true secondary growth, but instead of roots and rhizomes [4] .