How to identify it?
Cap
Cap 1.5- 5 cm across, conical at first, becoming broadly conic to convex; watery white to pale buff; surface smooth; with a striate margin. Flesh insubstantial, yellowish. Odour and taste not distinctive.
Gills
Gills free to narrowly adnexed, pale yellowish brown, becoming rusty cinnamon in age, close.

Scientific Classification

Phylum
Club fungi Class
Mushroom-forming fungi Order
Gilled fungi Family
Bolbitiaceae Genus
Bolbitius Species
Yellow fieldcap