Mountain Butter Bolete
Butyriboletus abieticola · Family Boletaceae · Updated October 2026
71US records
6states
Augbusiest month
71 US records since 1937 (14 in the last 10 years)
Last seen Aug 2, 2025 (about 15 months ago) near Cascadia, Linn County, OR, photographed by an iNaturalist user, with the ID agreed on by other iNaturalist users (research grade). Most US records come from California, Kansas and Idaho, and the busiest months are Aug, Sep and Jul. (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: Aug, Sep, Jul.
Where it's recorded
| State | Records | Latest sighting |
|---|---|---|
| California | 51 | Sep 15, 2024 |
| Kansas | 8 | – |
| Idaho | 5 | Aug 29, 1964 |
| Oregon | 4 | Aug 2, 2025 |
| Wyoming | 2 | Sep 25, 2023 |
| Washington | 1 | Aug 20, 1937 |
Top counties
- Sierra County, CA (18) · latest Oct 14, 1995
- Siskiyou County, CA (9) · latest Oct 5, 1984
- Wabaunsee County, KS (8)
- Shasta County, CA (5) · latest Jul 20, 1977
- Valley County, ID (4) · latest Aug 29, 1964
- Tuolumne County, CA (3) · latest Sep 15, 2024
- Humboldt County, CA (3) · latest Jun 23, 2021
- Tehama County, CA (2) · latest Oct 1, 1976
- El Dorado County, CA (2) · latest Aug 1, 2020
- Amador County, CA (2) · latest Aug 16, 1974
More on this species from GBIF.
Bring along
🍄
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.