Mycobank MB 517817
Thallus corticolous, crustose, continuous with finely uneven surface appearing smooth from a distance, green, dull, remaining opaque when wet (not subgelatinous), 25–50 µm thick, covering areas of up to 2 cm diam. at the upper surface of roots, margins not delimited by a hypothallus, without blackened basal layer and without back dots. Cortex absent. Algae chlorococcoid, cells round or more often ellipsoid to angular, irregularly arranged in the thallus, ca. 5–10 × 7–15 µm. Ascomata superficial, black, shiny, 0.1–0.2 mm diam., with black clypeus above that extends sideways as a saucer-like flat disc with a smooth surface, covering the upper 1/3 to 2/3 of the exciple in some perithecia or reaching the exciple base; exciple hyaline to pale brown below. Ostiole 10–25 µm wide. Hamathecium consisting of unbranched periphyses of 7–10 × 2–3 µm in gel near the ostiole. Asci clavate, 25–40 × 9-15 µm. Ascospores 8/ascus, hyaline, long ellipsoid, asymmetrical with one side flattened, in some views kidney- or D-shaped, (10–)12–15 × 4.5–6 µm, on average 12 × 5 µm (25 measured). Pycnidia unknown.
Only known from the type from roots of Alnus glutinosa along small rivulet in temperate forest. Irregularly submersed in fresh water.