Blue-Staining Suillus
Suillus caerulescens · Family Suillaceae · Updated October 2026
378US records
5states
Octbusiest month
378 US records since 1947 (237 in the last 10 years)
Last seen Jan 20, 2026 (about 9 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, Washington and Oregon, and the busiest months are Oct, Nov 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: Oct, Nov, Dec.
Where it's recorded
| State | Records | Latest sighting |
|---|---|---|
| California | 227 | Jan 20, 2026 |
| Washington | 87 | Dec 2, 2025 |
| Oregon | 58 | Dec 10, 2025 |
| Idaho | 5 | Nov 5, 1976 |
| Colorado | 1 | Aug 20, 1999 |
Top counties
- Marin County, CA (53) · latest Dec 8, 2025
- Santa Cruz County, CA (42) · latest Jan 20, 2026
- Mendocino County, CA (29) · latest Dec 27, 2018
- Sonoma County, CA (29) · latest Dec 28, 2025
- Clallam County, WA (28) · latest Oct 17, 2025
- Lane County, OR (22) · latest Nov 23, 2024
- San Mateo County, CA (21) · latest Jan 20, 2026
- Humboldt County, CA (14) · latest Oct 15, 2025
- King County, WA (12) · latest Oct 21, 2024
- Nevada County, CA (10) · latest Dec 15, 2023
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.