Slender Jack
Suillus umbonatus · Family Suillaceae · Updated October 2026
126US records
8states
Octbusiest month
126 US records since 1958 (20 in the last 10 years)
Last seen Nov 18, 2023 (about 3 years ago) near Arcata, Humboldt County, CA, photographed by an iNaturalist user, with the ID agreed on by other iNaturalist users (research grade). Most US records come from California, Colorado and Oregon, and the busiest months are Oct, Sep 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: Oct, Sep, Aug.
Where it's recorded
| State | Records | Latest sighting |
|---|---|---|
| California | 76 | Nov 18, 2023 |
| Colorado | 13 | Aug 27, 2022 |
| Oregon | 13 | Oct 18, 2019 |
| Washington | 9 | Oct 9, 2021 |
| Idaho | 6 | Aug 6, 2021 |
| Utah | 4 | Aug 24, 2001 |
| Wyoming | 4 | Aug 16, 1989 |
| Montana | 1 | Jul 28, 1982 |
Top counties
- Mendocino County, CA (23) · latest Nov 17, 2018
- Sierra County, CA (23) · latest Aug 31, 1989
- Humboldt County, CA (13) · latest Nov 18, 2023
- El Dorado County, CA (9) · latest Sep 16, 1983
- Tillamook County, OR (7) · latest Oct 18, 2019
- Pacific County, WA (5) · latest Oct 9, 2021
- Teton County, WY (4) · latest Aug 16, 1989
- Summit County, UT (3) · latest Aug 7, 1970
- Valley County, ID (3) · latest Sep 19, 1986
- Summit County, CO (3) · latest Aug 14, 1997
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.