Four chambered fruit, opened, with one seed left.
Airplane, complete with winglets! About 1" across. Kudos to Marisa for this find.
Found a wooden fence along the creek. ID provided by Chris Mallory from images I posted to Bug Guide. This is an introduced beetle species used as a biocontrol agent.
Photo didn't turn out very well, but the trunk was smooth and reddish-orange.
In the trail.