Some leaves have trunks.
Goethe said that all plants come from leaves. The rest is modified leaf. Maybe more than that. Look below. Some leaves have rocks.
Both deliver support, sun, water, anchorage and minerals. The only difference is that with a rock, you can sit within it and beside it.
Rocks are the lake versions of trunks. Leaves grow on the shore. Birches (below) enjoy the river version.
Leaves grow on the banks. And then there are the true artists: