Recently, we were studying leaves as one of the topics during our nature inquiry co-op. So I made little leaf books for both the boys to use, and decorated the front with washi tape.
The boys have been most busy hunting for various types of leaves (we referred to this leaf chart here). They pick the leaves, and stick them down into their books using washi tape. Instead of having to lug out a couple of rolls of tapes, I wound washi tape around ice-cream sticks and brought those "washi on a stick" samplers out.
We previously did another leaf book, but I'm liking how these books are filling up fast after every trip to the park!