Butter Bolete
Butyriboletus appendiculatus · Family Boletaceae · Updated October 2026
35US records
5states
Novbusiest month
35 US records since 1948 (0 in the last 10 years)
Last seen Nov 10, 2008 (about 18 years ago) near White Salmon, Klickitat County, WA, a preserved specimen in University of Washington Herbarium (WTU) - Macrofungi Collection. Most US records come from California, Washington and Oregon, and the busiest months are Nov, Dec and Oct. (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, Dec, Oct.
Where it's recorded
| State | Records | Latest sighting |
|---|---|---|
| California | 27 | Nov 16, 2005 |
| Washington | 4 | Nov 10, 2008 |
| Oregon | 2 | Jul 13, 1966 |
| Idaho | 1 | Aug 9, 1962 |
| New York | 1 | Jul 24, 1952 |
Top counties
- San Mateo County, CA (5) · latest Dec 13, 1969
- Amador County, CA (5) · latest Nov 25, 1975
- Marin County, CA (4) · latest Nov 21, 1982
- Tuolumne County, CA (3) · latest Dec 13, 1984
- Klickitat County, WA (3) · latest Nov 10, 2008
- Nevada County, CA (2) · latest Nov 9, 1975
- Santa Cruz County, CA (2) · latest Nov 16, 1975
- Whatcom County, WA (1) · latest Aug 14, 1963
- Adams County, ID (1) · latest Aug 9, 1962
- Butte County, CA (1) · latest Apr 5, 1948
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.