Anthoceros agrestis, commonly called field hornwort,[1][3] is a bryophyte of the family Anthocerotaceae.

[5] Anthoceros agrestis grows as a thin, dark green, rosette-like thallus up to 1.5 cm (0.6 in) in diameter, superficially resembling a leafless liverwort.

The spore-producing bodies lack a stalk or capsule but produce erect, cylindrical structures that turn black as they mature.

They then split open to reveal the spore-bearing central spindle and release the black spores.

It is listed as vulnerable in the Irish Red Data Book as it is known from fewer than five locations in the country.