Yellow Fieldcap

Bolbitius titubans

"Bolbitius titubans", also known as "Bolbitius vitellinus", is a widespread species of mushroom found in America and Europe. It grows chiefly on dung or heavily fertilized soil, and sometimes on grass. It is nonpoisonous.
Bolbitius titubans very delicate and fleeting - I saw a large grouping of them at around 9am in the morning - they are so airy and fragile that I was only able photograph the smallest stockiest specimen - the mature parasol shaped ones were swaying in the breeze. In a few short hours (about 1pm) I passed this same spot and they were all gone, shriveled into absolutely nothing by the sun. Bolbitius titubans,Fall,Geotagged,United States

Appearance

The mushroom cap is between 1.5–7 cm, and grows from egg-shaped when young to broadly convex, finally ending up nearly flat. The cap's color starts yellow or bright yellow, and fades to whitish or greyish with age. The gills are free from the stem or narrowly attached to it, are fragile and soft, and fade from whitish or pale yellowish to rusty cinnamon with age. The stem is 3–12 cm tall and 2–6 mm wide, is whitish-yellow with a fine mealy powdering, and is very delicate. The spores are brown, elliptical, and smooth.

The mushroom's edibility is unknown but it is too small to be worthwhile.

A similar species is "Bolbitius aleuriatus".

References:

Some text fragments are auto parsed from Wikipedia.

Taxonomy
KingdomFungi
DivisionBasidiomycota
ClassAgaricomycetes
OrderAgaricales
FamilyBolbitiaceae
GenusBolbitius
SpeciesB. vitellinus