Chaenothecopsis pusilla (Ach.) A. F. W. Schmidt

    Thallus made of a thin film (sometimes almost imperceptible!) of Chlorococccales algae colonies, greenish. Apothecia 0.5-1 mm high, composed of a head and a stipe; head: blackish lenticular capitulum or almost flat cupulate 0.15-0.3 mm diam., on top of  filiform stalk grey-brown. Ascospores ellipsoid to elongate, brownish, 1-septate, septum colourless and indistinct at maturity, but not septate in asci when immature, 5-7 x 2-2,5 µm. Chemical spot tests negative. Minuscule species, imperceptible, parasite or saprophyte of algae (free or not), found on dead wood, notably of Quercus. Several taxa, of which the status is not well established, are clustured under this name. Moreover this group includes other taxa of lichenized fungi (often considered by mycologists) which status is in doubt.*