Fall Phenomena: Witch Hats and Oak Apples

Witch hats and oak apples are descriptive nicknames for galls - abnormal structures that form on a leaf or stem in response to chemicals injected by insects or mites. This species-specific evolutionary relationship between the plant and organism showcases a unique give and take experience in the wild. Learn about these relationships, how galls form, what is happening inside them, and what they can tell us about our ecosystems.

This standalone program is part of the 4-session online Fall Phenomena Series. Register for the full series before it starts on 10/7/25 to get all 4 sessions (10/7 Witch Hats and Oak Apples; 10/21 Nature's Harvest; 11/4 Mighty Oaks; 11/18 Foraging Nature’s Cafe) for the price of 3. Recordings will be sent to registrants after each program.