The firecap is a large mutated mushroom resembling a toadstool. Firecaps can be used to make a number of recipes, including the Forest disease cure, firecap soup, firecap tasty souffle, glowing fungus puree and are used in creating Mentats.
- Four to seven individual picked firecaps can be found at the monorail elevator, on a cinder block foundation to the right of a crashed monorail all in one basket next to a skeleton in a lawn chair.
- Six grow in planters inside the Vault-Tec Agricultural Research Center -- one on the main floor, and five downstairs.
- Three can be found in a farm field near the I-59 and I-61 intersection. The farm location is on the image of a house on the main map. (location unclear, there is a US 61 but no I-61 in the game. Even then, they never meet.)
- Three can be found outside of the overseer's camp next to I-59 around Slocum's Joe, two next to the bus and one to the right of the building.
- One plant grows on a log on the side of the SH 91 due east of relay tower HN-B1-12. It is next to a truck with four Pulowski preservation shelters.
- One can be found when fast traveling to the Crosshair.
- One to three can be found due south from the fast travel location at Marigold Pavilion.