Thallus immersed in substrate. Photobiont: . Apothecia short, 0.5-1.0 mm high, 8-16 times as high as width of stalk. Stalk 0.05-0.08 mm diam., black in lower part and with a thick, yellowish-green pruina in upper part. Capitulum obconical to obovoid, with well-developed excipulum. Excipulum 0.14-0.26 mm diam. Hypothecium obconical with flat upper surface. Capitulum with a dense, yellowish-green or rarely reddish-brown pruina on lower side of excipulum. (When a reddish-brown pruina is present it yields violet-red feather-like or plate-like crystals in K.) Asci cylindrical, either without stalk and formed in chains or with a well-developed stalk and formed singly. Ascospores spherical, 5.0-7.6 µm diam., with an ornamentation formed of irregular, reticulate fissures surrounding small, polygonal areas. Chemistry: The yellow pruina of the apothecia contains vulpinic acid.