Cotylidia diaphana
Family Rickenellaceae · Updated October 2026
124US records
20states
Julbusiest month
124 US records since 1884 (10 in the last 10 years)
Last seen Nov 22, 2023 (about 3 years ago) near Guerneville, Sonoma County, CA, a preserved specimen in INSDC Sequences. Most US records come from New York, California and Washington, and the busiest months are Jul, Aug and Oct. (Data as of October 26, 2026; records can lag by weeks.)
⚠ Never eat a wild mushroom based on this site. We show where fungi have been recorded, nothing more. We never say any mushroom is edible or safe, and you shouldn't decide that from any website, app or photo. Many deadly mushrooms look like harmless ones. If someone may have eaten a wild mushroom, call Poison Control at 1-800-222-1222 right away.
Lookalike warning. Many mushrooms, including deadly ones, closely resemble each other, and the only reliable identification comes from an expert looking at the actual specimen (often with spore prints or microscopy). Never use a name, photo or record count on this page to decide what something is.
When it's recorded
Records by month, all years. Busiest: Jul, Aug, Oct.
Where it's recorded
Top counties
- Tompkins County, NY (19) · latest Aug 18, 1947
- King County, WA (11) · latest Oct 28, 1968
- Hennepin County, MN (10) · latest Jul 16, 2016
- Onondaga County, NY (8) · latest 1890-10
- Alameda County, CA (7) · latest Nov 14, 1941
- Marin County, CA (4) · latest Mar 1, 1941
- Sonoma County, CA (3) · latest Nov 22, 2023
- Montgomery County, AL (3)
- Nicollet County, MN (2) · latest Aug 22, 2022
- Weber County, UT (2) · latest Aug 25, 1993
More on this species from GBIF.
Bring along
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Regional mushroom field guideSee on Amazon🍄
Folding mushroom knife with brushSee on Amazon🍄
Wicker foraging basketSee on Amazon🍄
10x hand lens / loupeSee on Amazon🍄
Spore print paperSee on AmazonAs an Amazon Associate we earn from qualifying purchases.