Brown Cubical Rot Of Birch
Fomitopsis betulina · Family Fomitopsidaceae · Updated October 2026
2,239US records
28states
Sepbusiest month
2,239 US records since 1874 (1,545 in the last 10 years)
Last seen Oct 4, 2026 (about 3 weeks ago) in Clark County, WI, photographed by an iNaturalist user, with the ID agreed on by other iNaturalist users (research grade). Most US records come from New Jersey, Massachusetts and Pennsylvania, and the busiest months are Sep, Oct and Aug. (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: Sep, Oct, Aug.
Where it's recorded
Top counties
- Middlesex County, MA (80) · latest Sep 11, 2026
- Sussex County, NJ (73) · latest Sep 25, 2021
- Ocean County, NJ (65) · latest Mar 8, 2024
- Burlington County, NJ (63) · latest Apr 26, 2026
- Mercer County, NJ (55) · latest May 4, 2019
- Morris County, NJ (55) · latest Mar 10, 2025
- Essex County, MA (55) · latest Apr 26, 2026
- Chittenden County, VT (49) · latest Aug 14, 2026
- St. Louis County, MN (46) · latest Sep 21, 2026
- Hunterdon County, NJ (33) · latest Aug 25, 2019
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.