Cyathus striatus

Common Name: None.
Description: Fruit body variable but generally 6-8mm across, 7-10mm high, shaped like an obtuse inverted cone; outer surface shiny, light to dark gray, and fluted; containing several gray 'eggs' initially concealed by a whitish membrane across the mouth of the cup, which withers at maturity.
Habitat: scattered or in groups on dead wood or vegetable debris in open woods. Common. Found widely distributed throughout North America.
Edible: Not edible.

Source: Mushrooms of North America by Roger Phillips.