Ponderous Slippery Jack
Suillus ponderosus · Family Suillaceae · Updated October 2026
130US records
4states
Novbusiest month
130 US records since 1947 (34 in the last 10 years)
Last seen Nov 9, 2025 (about 12 months ago) near Santa Cruz, Santa Cruz County, CA, photographed by an iNaturalist user, with the ID agreed on by other iNaturalist users (research grade). Most US records come from California, Oregon and Washington, and the busiest months are Nov, Oct and Dec. (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: Nov, Oct, Dec.
Where it's recorded
| State | Records | Latest sighting |
|---|---|---|
| California | 98 | Nov 9, 2025 |
| Oregon | 23 | Oct 28, 2023 |
| Washington | 8 | Oct 31, 2024 |
| New Mexico | 1 | Sep 22, 2024 |
Top counties
- Mendocino County, CA (55) · latest Nov 11, 2023
- Marin County, CA (11) · latest Dec 8, 2023
- Santa Cruz County, CA (9) · latest Nov 9, 2025
- Del Norte County, CA (7) · latest Oct 23, 1972
- Lane County, OR (7) · latest Nov 12, 2022
- Humboldt County, CA (6) · latest Nov 19, 2021
- Sonoma County, CA (4) · latest Nov 4, 2016
- Napa County, CA (3) · latest Dec 19, 1967
- Thurston County, WA (3) · latest Oct 31, 2024
- Tillamook County, OR (2) · latest Oct 26, 1970
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.