Poison ivy

Description:

Poison ivy stems and roots on oak (first four photos) and pine (last two photos). The plant often grows as a climbing vine, with aerial roots that attach to tree trunks. Causes a painful rash and there are rhymes to remind people not to touch it, like "hairy vine, no friend of mine."

Notes:

Just above the leaves in the last photo, you can see the curving base of the vine, about as big around as your wrist, where it emerged from the ground and fused with the tree trunk.