Mushrooms in Boulder County, Colorado
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.
Too few past records in January here to list species.
Too few past records in February here to list species.
Too few past records in March here to list species.
Usually recorded in April here:
Weather Earthstar Geastrum corollinum2 April records across all years- Clitocybe praemagna2 April records across all years
Usually recorded in May here:
- Pholiota carbonaria5 May records across all years
Horse Mushroom Agaricus arvensis3 May records across all years
Turf Mottlegill Panaeolus fimicola3 May records across all years
Spring Polypore Lentinus arcularius3 May records across all years
Spring Cavalier Melanoleuca cognata3 May records across all years- Hebeloma evensoniae3 May records across all years
Pale Oyster Pleurotus pulmonarius3 May records across all years
Psathyrella pennata2 May records across all years
Cryptic Globe Fungus Cryptoporus volvatus2 May records across all years- Hebeloma velatum2 May records across all years
Big Sheath Mushroom Volvopluteus gloiocephalus2 May records across all years- Hebeloma subfastigiatum2 May records across all years
Usually recorded in June here:
- Conocybe juniana3 June records since 2011
Pleated Inkcap Parasola plicatilis2 June records since 2011
Snowmelt Clitocybe Clitocybe glacialis2 June records since 2011
Lawyer's Wig Coprinus comatus2 June records since 2011
Pandas Thumb Phallus impudicus2 June records since 2011
Usually recorded in July here:
Fly Agaric Amanita muscaria9 July records since 2011
Ruby King Bolete Boletus rubriceps6 July records since 2011
Saffron Milk-Cap Lactarius deliciosus4 July records since 2011
Giant Lentinus Neolentinus ponderosus3 July records since 2011
Common Bird's Nest Crucibulum laeve3 July records since 2011- Tyromyces leucospongius3 July records since 2011
- Snowmelt Clitocybe Clitocybe glacialis2 July records since 2011
Mulch Maids Leratiomyces percevalii2 July records since 2011
Usually recorded in August here:
- Fly Agaric Amanita muscaria13 August records since 2011
Scaly Tooth Sarcodon imbricatus11 August records since 2011
Laccaria nobilis10 August records since 2011- Ruby King Bolete Boletus rubriceps8 August records since 2011
Short-Stalked Suillus Suillus brevipes8 August records since 2011
Blue-Staining Slippery Jack Suillus tomentosus8 August records since 2011
Blue Corky Spine Fungus Hydnellum caeruleum7 August records since 2011
Common Puffball Lycoperdon perlatum7 August records since 2011
Northern Bearded Milkcap Lactarius repraesentaneus6 August records since 2011
Purple Spindles Alloclavaria purpurea5 August records since 2011
Soapy Knight Tricholoma saponaceum5 August records since 2011- Hydnellum glaucopus4 August records since 2011
Usually recorded in September here:
Dune Stinkhorn Phallus hadriani8 September records since 2011- Short-Stalked Suillus Suillus brevipes7 September records since 2011
Conifer Mazegill Gloeophyllum sepiarium4 September records since 2011- Blue-Staining Slippery Jack Suillus tomentosus4 September records since 2011
Birch Knight Tricholoma fulvum3 September records since 2011
Crab Brittlegill Russula xerampelina3 September records since 2011
Purplepore Bracket Trichaptum abietinum3 September records since 2011
Bitter Tooth Hydnellum scabrosum3 September records since 2011- Crucibulum cyathiforme3 September records since 2011
- Lawyer's Wig Coprinus comatus3 September records since 2011
- Common Bird's Nest Crucibulum laeve2 September records since 2011
Matt Knight Tricholoma imbricatum2 September records since 2011
Usually recorded in October here:
Phellinus viticola5 October records across all years
Field Mushroom Agaricus campestris5 October records across all years
Forest Lamb Albatrellus ovinus4 October records across all years
Honey Fungus Armillaria mellea4 October records across all years
Shaggy Parasol Chlorophyllum rhacodes4 October records across all years
Salty Mushroom Agaricus bernardii3 October records across all years
Fluted Bird's Nest Cyathus striatus2 October records across all years
Brown Funnel Polypore Coltricia perennis2 October records across all years
Usually recorded in November here:
- Cylindrobasidium corrugum7 November records across all years
Usually recorded in December here:
- Cryptic Globe Fungus Cryptoporus volvatus2 December records across all years
Most-recorded species
| # | Species | Records |
|---|---|---|
| 1 | 29 | |
| 2 | 25 | |
| 3 | 21 | |
| 4 | 20 | |
| 5 | 19 | |
| 6 | 17 | |
| 7 | 17 | |
| 8 | 16 | |
| 9 | 16 | |
| 10 | 16 | |
| 11 | 15 | |
| 12 | 15 | |
| 13 | 14 | |
| 14 | 14 | |
| 15 | 13 |
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: Aug, Sep, Jul.
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.
- 1Jul 30, 2026Fly Agaric Amanita muscariain Roosevelt National Forest, CO · iNaturalist photo, research grade · original record
- 2Jul 2, 2026Ruby King Bolete Boletus rubricepsnear Allenspark, CO · iNaturalist photo, research grade · original record
- 3Jun 21, 2026Pale Oyster Pleurotus pulmonariusnear Eldorado Springs, CO · iNaturalist photo, research grade · original record
- 4May 13, 2026Giant Lentinus Neolentinus ponderosusin Eldorado Canyon State Park, CO · iNaturalist photo, research grade · original record
- 5
Apr 25, 2026Spring Fieldcap Agrocybe praecoxnear Boulder, CO · iNaturalist photo, research grade · original record - 6
Oct 20, 2025Western Painted Suillus Suillus lakeiin Walker Ranch, CO · iNaturalist photo, research grade · original record - 7Oct 12, 2025Shaggy Parasol Chlorophyllum rhacodesnear Eldorado Springs, CO · iNaturalist photo, research grade · original record
- 8Oct 12, 2025Shaggy Parasol Chlorophyllum rhacodesnear Louisville, CO · iNaturalist photo, research grade · original record
- 9Oct 7, 2025Agaricus malangelusnear Boulder, CO · iNaturalist photo, research grade · original record
- 10Sep 28, 2025Short-Stalked Suillus Suillus brevipesin Roosevelt National Forest, CO · iNaturalist photo, research grade · original record
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How we built this page
2,985 records of mushrooms, shelf fungi and polypores (class Agaricomycetes) that fall inside this county's Census boundary. Licenses: 2,547 CC0 and 438 CC BY 4.0. See about the data for the full citation.