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Mushrooms in Contra Costa County, California
Updated October 2026 · from open GBIF records
2,990mushroom records
394species recorded
Janbusiest month
2,990 records since 1902 (2,524 in the last 10 years)
Fruiting now
Based on past sightings (mostly since 2011; all years where recent records are few), not a forecast. Weather and place matter a lot, and a listing here says nothing about whether a mushroom is safe.
Usually recorded in January here:
California Jack O' Lantern Omphalotus olivascens42 January records since 2011
Yellow Fieldcap Bolbitius titubans37 January records since 2011
Hairy Curtain Crust Stereum hirsutum31 January records since 2011
Fly Agaric Amanita muscaria31 January records since 2011
Chip Cherries Leratiomyces ceres27 January records since 2011
Golden Milk Cap Lactarius alnicola25 January records since 2011
Turkeytail Trametes versicolor23 January records since 2011
Wood Blewit Lepista nuda21 January records since 2011
Red Cage Clathrus ruber19 January records since 2011
Common Porecrust, Split Gill Fungus Schizophyllum commune18 January records since 2011
Mulch Maids Leratiomyces percevalii18 January records since 2011
Western Jumbo Gym Gymnopilus ventricosus18 January records since 2011
Usually recorded in February here:
- Mulch Maids Leratiomyces percevalii27 February records since 2011
- Turkeytail Trametes versicolor21 February records since 2011
- Common Porecrust, Split Gill Fungus Schizophyllum commune15 February records since 2011
Redwood Rooter Caulorhiza umbonata15 February records since 2011
Sulphur Tuft Hypholoma fasciculare11 February records since 2011
Bittersweet Orange Ringless Amanita Amanita velosa11 February records since 2011- Hairy Curtain Crust Stereum hirsutum10 February records since 2011
- California Jack O' Lantern Omphalotus olivascens10 February records since 2011
- Golden Milk Cap Lactarius alnicola10 February records since 2011
- Yellow Fieldcap Bolbitius titubans8 February records since 2011
- Wood Blewit Lepista nuda8 February records since 2011
Bleeding Fairy Helmet Mycena haematopus7 February records since 2011
Usually recorded in March here:
- Turkeytail Trametes versicolor17 March records since 2011
- Mulch Maids Leratiomyces percevalii15 March records since 2011
- Bittersweet Orange Ringless Amanita Amanita velosa14 March records since 2011
- Hairy Curtain Crust Stereum hirsutum11 March records since 2011
- Common Porecrust, Split Gill Fungus Schizophyllum commune10 March records since 2011
Cabbage Parachute Gymnopus brassicolens5 March records since 2011
Pungent Slippery Jack Suillus pungens5 March records since 2011
Blushing Bride Amanita novinupta5 March records since 2011- California Jack O' Lantern Omphalotus olivascens5 March records since 2011
- Birch Mazegill, Gilled Polypore Lenzites betulinus5 March records since 2011
California Golden Chanterelle Cantharellus californicus4 March records since 2011
Spring Fieldcap Agrocybe praecox4 March records since 2011
Usually recorded in April here:
- Bittersweet Orange Ringless Amanita Amanita velosa22 April records since 2011
- Turkeytail Trametes versicolor12 April records since 2011
- Birch Mazegill, Gilled Polypore Lenzites betulinus12 April records since 2011
Artist's Conk Ganoderma brownii11 April records since 2011- Hairy Curtain Crust Stereum hirsutum11 April records since 2011
- Blushing Bride Amanita novinupta9 April records since 2011
- Mulch Maids Leratiomyces percevalii9 April records since 2011
Deer Mushroom Pluteus cervinus7 April records since 2011- Cabbage Parachute Gymnopus brassicolens7 April records since 2011
- Spring Fieldcap Agrocybe praecox6 April records since 2011
- California Jack O' Lantern Omphalotus olivascens5 April records since 2011
- Yellow Fieldcap Bolbitius titubans4 April records since 2011
Usually recorded in May here:
- Turkeytail Trametes versicolor5 May records since 2011
- Blushing Bride Amanita novinupta4 May records since 2011
- Bleeding Fairy Helmet Mycena haematopus3 May records since 2011
- Artist's Conk Ganoderma brownii2 May records since 2011
Western Giant Puffball Calvatia booniana2 May records since 2011- Common Porecrust, Split Gill Fungus Schizophyllum commune2 May records since 2011
Golden Bracket Fuscoporia gilva2 May records since 2011- Hairy Curtain Crust Stereum hirsutum2 May records since 2011
Death Cap Amanita phalloides2 May records since 2011- Cabbage Parachute Gymnopus brassicolens2 May records since 2011
Usually recorded in June here:
Glistening Ink-Cap Coprinellus micaceus2 June records since 2011- Turkeytail Trametes versicolor2 June records since 2011
Usually recorded in July here:
Oak Bracket Pseudoinonotus dryadeus2 July records since 2011
California Agaricus Agaricus californicus2 July records since 2011- Common Porecrust, Split Gill Fungus Schizophyllum commune2 July records since 2011
Usually recorded in August here:
Western Chicken-Of-The-Woods Laetiporus gilbertsonii5 August records across all years- Tulostoma cyclophorum2 August records across all years
Short-Stemmed Russula Russula brevipes2 August records across all years- Turkeytail Trametes versicolor2 August records across all years
- Death Cap Amanita phalloides2 August records across all years
Usually recorded in September here:
- Western Chicken-Of-The-Woods Laetiporus gilbertsonii10 September records since 2011
Brown Cubical Rot Laetiporus conifericola2 September records since 2011
Bohemian Truffle Pisolithus arhizus2 September records since 2011
Blushing Rosette Abortiporus biennis2 September records since 2011
Usually recorded in October here:
- Western Chicken-Of-The-Woods Laetiporus gilbertsonii16 October records since 2011
- Bohemian Truffle Pisolithus arhizus6 October records since 2011
Pisolithus tinctorius5 October records since 2011- Artist's Conk Ganoderma brownii3 October records since 2011
- Glistening Ink-Cap Coprinellus micaceus2 October records since 2011
- Chip Cherries Leratiomyces ceres2 October records since 2011
- Red Cage Clathrus ruber2 October records since 2011
- California Jack O' Lantern Omphalotus olivascens2 October records since 2011
- Cabbage Parachute Gymnopus brassicolens2 October records since 2011
Usually recorded in November here:
- Western Chicken-Of-The-Woods Laetiporus gilbertsonii16 November records since 2011
- Death Cap Amanita phalloides9 November records since 2011
- Chip Cherries Leratiomyces ceres9 November records since 2011
Liver Bolete Suillellus amygdalinus9 November records since 2011- Yellow Fieldcap Bolbitius titubans7 November records since 2011
- California Jack O' Lantern Omphalotus olivascens7 November records since 2011
- Golden Milk Cap Lactarius alnicola6 November records since 2011
- Hairy Curtain Crust Stereum hirsutum6 November records since 2011
Ballen's American Caesar Amanita calyptroderma6 November records since 2011- Cabbage Parachute Gymnopus brassicolens5 November records since 2011
Honey Fungus Armillaria mellea5 November records since 2011- Sulphur Tuft Hypholoma fasciculare5 November records since 2011
Usually recorded in December here:
- California Jack O' Lantern Omphalotus olivascens36 December records since 2011
- Golden Milk Cap Lactarius alnicola27 December records since 2011
- Turkeytail Trametes versicolor23 December records since 2011
- Hairy Curtain Crust Stereum hirsutum23 December records since 2011
- Fly Agaric Amanita muscaria21 December records since 2011
- Pungent Slippery Jack Suillus pungens18 December records since 2011
- Western Jumbo Gym Gymnopilus ventricosus14 December records since 2011
- Liver Bolete Suillellus amygdalinus13 December records since 2011
- Cabbage Parachute Gymnopus brassicolens11 December records since 2011
- Sulphur Tuft Hypholoma fasciculare11 December records since 2011
- Death Cap Amanita phalloides10 December records since 2011
- Yellow Fieldcap Bolbitius titubans10 December records since 2011
⚠ 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.
Most-recorded species
| # | Species | Records |
|---|---|---|
| 1 | 109 | |
| 2 | 108 | |
| 3 | 99 | |
| 4 | 79 | |
| 5 | 73 | |
| 6 | 70 | |
| 7 | 61 | |
| 8 | 60 | |
| 9 | 55 | |
| 10 | 54 | |
| 11 | 50 | |
| 12 | 49 | |
| 13 | 48 | |
| 14 | 47 | |
| 15 | 44 |
Being on this list doesn't mean a mushroom is common, easy to identify or safe. It only means it has been recorded here often.
Best months to look
Records by month, all years. Busiest: Jan, Dec, Feb.
Sightings map
● Each dot is a place with at least one record (rounded to about 1 km). Locations can be approximate, and many are on private land. Numbered blue circles are recent sightings, shown only to a general area of about 10 km.
Recent sightings
The 10 most recent dated records in this county, newest first. Data as of October 26, 2026. Records can take weeks or more to reach GBIF, so the newest finds may not show yet. Places are given only as a public park or forest (from the USGS Protected Areas Database) or the nearest town, and the numbered circles on the map cover a general area, not an exact spot.
- 1Sep 5, 2026Western Chicken-Of-The-Woods Laetiporus gilbertsoniiin Point Pinole Regional Shoreline, CA · iNaturalist photo, research grade · original record
- 2Jul 22, 2026Red Cage Clathrus rubernear Moraga, CA (location blurred by the observer) · iNaturalist photo, research grade · original record
- 3
Jul 4, 2026Patrician Deer Mushroom Pluteus petasatusnear Orinda, CA · iNaturalist photo, research grade · original record - 4May 10, 2026Death Cap Amanita phalloidesin Huckleberry Botanic Regional Preserve, CA · iNaturalist photo, research grade · original record
- 5May 4, 2026Death Cap Amanita phalloidesnear Orinda, CA · iNaturalist photo, research grade · original record
- 6May 3, 2026Patrician Deer Mushroom Pluteus petasatusnear Clayton, CA · iNaturalist photo, research grade · original record
- 7May 2, 2026Western Giant Puffball Calvatia booniananear Martinez, CA · iNaturalist photo, research grade · original record
- 8Apr 26, 2026Turkeytail Trametes versicolornear Hercules, CA · iNaturalist photo, research grade · original record
- 9Apr 25, 2026Western Giant Puffball Calvatia boonianain Mount Diablo State Park, CA · iNaturalist photo, research grade · original record
- 10Apr 24, 2026Turkeytail Trametes versicolorin Tilden Regional Park, CA · iNaturalist photo, research grade · original record
Many sightings are on private land. Always get the landowner's permission, and follow the rules of parks and forests, which often limit or ban collecting.
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.
How we built this page
2,990 records of mushrooms, shelf fungi and polypores (class Agaricomycetes) that fall inside this county's Census boundary. Licenses: 1,047 CC0 and 1,943 CC BY 4.0. See about the data for the full citation.