Trees are also too many things to be one thing.

https://eukaryotewritesblog.com/2021/05/02/theres-no-such-th... crops up on HN periodically.

    “Trees” are not a coherent phylogenetic category. On the
    evolutionary tree of plants, trees are regularly
    interspersed with things that are absolutely, 100% not
    trees. This means that, for instance, either:

    - The common ancestor of a maple and a mulberry tree was
      not a tree.
    - The common ancestor of a stinging nettle and a
      strawberry plant was a tree.
    - And this is true for most trees or non-trees that you
      can think of.