Macrofungi of Brant, Norfolk, and Waterloo
You can probably think of Carolinian plants: sassafras (Sassafras albidum), tulip tree (Liriodendron tulipifera), and pawpaw (Asimina triloba) are just a few of around 200 plant species which occur in the Carolinian Zone and nowhere else in Canada. Animals, too: Acadian flycatcher (Empidonax virescens), Louisiana waterthrush (Parkesia motacilla), and dozens of insects. But are there Carolinian fungi? Dr. Greg Thorn’s lab at Western University in London, Ontario is answering this question by completing an inventory of the macrofungi of the Carolinian Zone. The annotated checklist of macrofungi of Brant County, Norfolk County, and Waterloo Region is the first part of what will eventually be a much larger inventory.
Why study fungi?
Fungi are a huge kingdom of life on Earth. By some estimates, there are around five times as many species of fungi as there are species of plants. To put this in a regional perspective, there are around 2,000 species of vascular plants in the Carolinian Zone, which means there could be around 10,000 species of fungi. This includes everything from single-celled yeasts to tiny molds right up to huge mushroom relatives like the giant puffball (Calvatia gigantea).
All fungi play significant ecological roles. Fungi that decompose wood and other plant material are called saprobes and are some of the dominant decomposers in terrestrial ecosystems. They are, in fact, some of the only organisms capable of breaking down cellulose and lignin, the complex molecules that make up wood; if fungi had never evolved this capability, dead trees would just pile up for millions of years! Other fungi form connections with plant roots called mycorrhizae; these symbiotic relationships between fungus and plant are critical to the integrity of forests, grasslands, and other terrestrial habitats. Notably, trees like oaks, pines, and spruces frequently produce mycorrhizae and probably require these relationships for their survival. Orchids also form mycorrhizae, and most orchid seeds cannot germinate without first connecting to a hypha (a thread-like structure) of a specific fungus.
Fungus communities can function as indicators of ecological integrity, air quality, and environmental change. Lichens in particular have been studied as indicators of air quality since many species are highly sensitive to certain pollutants. A baseline inventory of fungi like the one here can be used as a monitoring tool by allowing us to study how the community changes over time.
Despite their diversity and their immense importance to ecological and human health, fungi are chronically under-studied compared to plants, birds, fish, and even insects. Some estimates are that only around five percent of fungi have been described by scientists, and new species are being discovered every year even in densely populated parts of the world like the Great Lakes region of North America. The Brant, Norfolk, and Waterloo macrofungus inventory is the first of its kind in Ontario and one of the first in Canada.
What are macrofungi?
“Macrofungi” are quite simply big fungi. There is no formal definition, but typically it means they produce sporocarps (spore-producing fruiting bodies) that can be seen with the naked eye. For the purposes of this inventory, it might be better to list the things that aren’t included. It doesn’t include most plant-pathogenic fungi like rusts, smuts, powdery mildews, and the thousands of organisms that cause leaf spots, curls, and mutations. Yeasts, which are mostly single-celled, are excluded, as well as thousands of organisms called “molds” which produce tiny, mostly asexual fruiting bodies.
Macrofungi have a vast array of growth forms. The most familiar form is the mushroom: a cap with gills on a stem. Some gilled fungi are sessile meaning they don’t produce a stem. Other macrofungi produce spores in pores, teeth, cups, or simply covering a flat surface. For a more detailed summary of different growth forms of macrofungi, I recommend the illustrated book The Kingdom of Fungi by Jens H. Petersen (2013).
The Inventory
The initial checklist of macrofungi of Brant County, Norfolk County, and Waterloo Region was produced by William Van Hemessen for his M.Sc. at Western University (click here to download a copy of the thesis). The checklist was produced from a combination of historical data, field work, and citizen science, including over 6,000 records submitted to iNaturalist by expert and amateur mycologists.
Version 2.0 of the checklist was released in June of 2025 and includes an additional 900 herbarium records plus new records collected during ongoing field work. As of June 2025, the checklist includes 1,205 species of macrofungi, including:
- 770 species in Brant County
- 580 species in Norfolk County
- 558 species in Waterloo Region
How to participate
The checklist is a living document and new species are continually being added. You can contribute to the checklist by joining the Fungi of Carolinian Canada project on iNaturalist and submitting your own fungus observations.
Remember that a single photo does not provide enough information to identify a mushroom or any other fungus. The photo of Caloboletus inedulis on the left is a great example of how to illustrate key features of a fungus: the top and bottom of the cap, the stem, a cross-section of the sporocarp to show staining, and basal mycelium. But there’s more! Identifying fungi is so much more interactive than plants or animals. You should also make note of:
- Any smell (flowery, fishy, fruity, garlicy…be creative!)
- What it was growing on (the ground, dead wood, sand, a rock, poop, etc.)
- What was growing around it (species of trees and other plants)
Acknowledgements
Dr. Greg Thorn (Western University) and Dr. Troy McMullin (Canadian Museum of Nature) lent tremendous support and assistance in preparing the initial checklist, and secured funding for field work and genetic sequencing of almost 200 specimens included in the inventory. Lauren Jones, Lauren Vanderlingen, and residents of the (Haudenosaunee) Six Nations of the Grand River who participated in forays on the reserve helped contribute information from a significant gap in the study area. The Grand River Conservation Authority, Nature Conservancy of Canada, Rare Charitable Research Reserve, and Long Point Basin Land Trust enthusiastically permitted research on their properties.
Most importantly, naturalists of all skill levels contributed immense amounts of data to this project. A complete list is impossible, but a few individuals deserve special mention for contributing their knowledge and keen eyes: Luke Eckstein, John Wellhauser, Natalie Doerr, Jeff Leader, Pauline Catling, and many others.
References
Petersen, J.H. 2013. The Kingdom of Fungi. Princeton University Press. 272 pp.
Van Hemessen, W.D. 2025. Macrofungi of Brant County, Norfolk County, and Waterloo Region, Ontario. M.Sc. thesis, Western University. Electronic Thesis and Dissertation Repository 10754.