I'm thinking of the oak leaves etc that gather in my yard... the stems are pretty thick, like the selvage edge on FG tape... that's gonna make air bubbles, right? Or were you gonna lay them on top of the glass and bury them? I guess once you got the leaf proper buried, you could cabinet scraper the stem flat.

If you could press them flat first... really flat...

I have thought about using leaves as masks before, or pressing them into the paint as it dries, then lifting them out, to leave the impression. Truthfully, probably be better off with paper templates then, or stamps.

There are a lot of handmade papers out there, you could probably get good effects just with cut out leaves. Maybe even fabric. Maybe even RealTree(TM)... but it woudn't take much, 3 or 5 leaves "falling", spiraling around the foredeck.

Mostly though, in the fall, I will just collect one or two and place them on deck as I paddle. Sometimes they land there themselves. Then they can come off and I get new ones next time... sometimes... lol.