Yellow Fieldcap Bolbitius titubans (Bull.) Fr. syn. B. vitellinus (Pers.) Fr. (illustrated 50% life size) Cap 1–4cm across, acorn-shaped then bell-shaped, finally expanding to almost flat; chrome-yellow at first, fading to grey-brown at the margin; , very thin and almost transparent, somewhat viscid when young, drying shiny with age, deeply grooved at the margin. Stem 30–100×2–4mm; whitish-yellow, with a fine, mealy powdering, base downy; very delicate, hollow. Flesh thin and membranous above the gills. Gills crowded; pale yellow at first, later cinnamon or rusty. Spores 11–15×6–9¼, elliptical, smooth. Spore print rust-brown. Habitat on rotting straw, manured grassland, or wood chips; summer to late autumn. Very common. Not edible.