Mycology is the study of fungi — hence the Illinois Mycology Association. During mushroom season in Illinois, mid-April to early November, the  Illinois Mycological Association members conduct surveys around Chicagoland a few times a month. Mycologist Dr. Patrick Leacock identifies fungi collected by the Illinois Mycological Association at the St. Mihiel Woods-East nature preserve in Tinley Park on Oct. 26, 2024. (Tess Crowley/Chicago Tribune) Melissa Fei lays fungi on a blanket after a fungi collection by the Illinois Mycological Association at the St. Mihiel Woods-East nature preserve in Tinley Park on Oct. 26, 2024. (Tess Crowley/Chicago Tribune) Kate Golembiewski, dressed in a bridal veil stinkhorn mushroom Halloween costume, holds fungi while listening as mycologist Dr. Patrick Leacock identifies fungi collected by the Illinois Mycological Association at the St. Mihiel Woods-East nature preserve in Tinley Park on Oct. 26, 2024. (Tess Crowley/Chicago Tribune) John Willis, 12, collects fungi with the Illinois Mycological Association at the St. Mihiel Woods-East nature preserve in Tinley Park on Oct. 26, 2024. (Tess Crowley/Chicago Tribune) A tray lays open with fungi specimens that Kate Peltz collected with the Illinois Mycological Association at the St. Mihiel Woods-East nature preserve. (Tess Crowley/Chicago Tribune) A member of the Illinois Mycological Association wears a witch hat as a Halloween costume while collecting fungi at the St. Mihiel Woods-East nature preserve. (Tess Crowley/Chicago Tribune) John Willis, 12, left, looks in awe at a blewit mushroom that Gino Albert found with the Illinois Mycological Association at the St. Mihiel Woods-East nature preserve in Tinley Park on Oct. 26, 2024. (Tess Crowley/Chicago Tribune) President of the Illinois Mycological Association Matt Nelsen wears a fungi-infected ant Halloween costume while collecting fungi at the St. Mihiel Woods-East nature preserve. (Tess Crowley/Chicago Tribune) A member of the Illinois Mycological Association collects fungi at the St. Mihiel Woods-East nature preserve in Tinley Park. (Tess Crowley/Chicago Tribune) Member of the Illinois Mycological Association and volunteer at the Field Museum Madison Biesinger looks at fungi collected by Kate Peltz at the St. Mihiel Woods-East nature preserve in Tinley Park on Oct. 26, 2024. Some of the collected fungi will be taken to the Field Museum for DNA analysis. (Tess Crowley/Chicago Tribune) Neil Fei, 8, in a mushroom hat that he wears as a Halloween costume every year, collects fungi with the Illinois Mycological Association at the St. Mihiel Woods-East nature preserve in Tinley Park on Oct. 26, 2024. (Tess Crowley/Chicago Tribune) Mycologist Dr. Patrick Leacock explains that the fungi in his hand is poisonous after a fungi collection by the Illinois Mycological Association at the St. Mihiel Woods-East nature preserve in Tinley Park. (Tess Crowley/Chicago Tribune) DJ Jones wears a gorilla Halloween costume while collecting fungi with the Illinois Mycological Association at the St. Mihiel Woods-East nature preserve in Tinley Park on Oct. 26, 2024. (Tess Crowley/Chicago Tribune) Kate Peltz wears a forest elf fairy Halloween costume while collecting fungi with the Illinois Mycological Association at the St. Mihiel Woods-East nature preserve. (Tess Crowley/Chicago Tribune) Molly Willis, 6, searches for fungi with the Illinois Mycological Association at the St. Mihiel Woods-East nature preserve. (Tess Crowley/Chicago Tribune) Mycologist Dr. Patrick Leacock identifies fungi collected by the Illinois Mycological Association as puffball mushrooms at the St. Mihiel Woods-East nature preserve on Oct. 26, 2024. (Tess Crowley/Chicago Tribune) Kate Peltz wears a forest elf fairy Halloween costume while collecting fungi with the Illinois Mycological Association at the St. Mihiel Woods-East nature preserve in Tinley Park on Oct. 26, 2024. (Tess Crowley/Chicago Tribune) Kate Peltz wears a forest elf fairy Halloween costume while collecting fungi with the Illinois Mycological Association at the St. Mihiel Woods-East nature preserve in Tinley Park on Oct. 26, 2024. (Tess Crowley/Chicago Tribune)