Thallus: superficial, leprose (farinaceous), soft and ecorticate, usually well developed, thin, bright yellow-green, occasionally almost immersed; in young parts: composed of +discrete patches of loosely arranged photobiont chains and fungal hyphae, that usually fuse and form a thin, +continuous cover, and from this basal crust fungal hyphae densely beset with crystals project, giving the thallus surface a soft texture; prothallus: sometimes evident, composed of loosely organized, white hyphae photobiont: Stichococcus, the cells elongate or rectangular, in short chains, transversely septate, the cells < 13 mm wide Apothecia: often absent, but abundant when present, scattered to grouped, 1.6-2.7 mm tall, slender; head and stalk: covered by a yellowish green pruina, black beneath stalk: 0.06-0.10 mm in diam.; upper part: with often branched, laterally projecting hyphae 5-20 µm long, densely covered by yellow crystals; lower part: sometimes epruinose and black capitulum: spherical, 0.1-0.2 mm in diam. mazaedium: sulfur yellow or straw yellow, sometimes pale brown exciple: absent or poorly developed; hypothecium: pale brown, strongly convex, knob-like, consisting of intricately interwoven hyphae, that are slightly sclerotized towards the surface of the hypothecium asci: formed in chains, often irregular, 12-15 x 2-3 µm, with uniseriate to irregularly arranged spores ascospores: hyaline or pale yellowish, spherical, 2.5-3 µm in diam., with a very minute ornamentation of tiny warts very difficult to discern in the light microsocpe Anamorph: hyphomycetous conidia: one-celled, 2-3 x 1 µm Spot tests: thallus K-, C-, KC-, P- Secondary metabolites: thallus and pruina with vulpinic acid, pulvinic acid and pulvinic acid dilactone. Substrate and ecology: on soil or on roots protected from precipitation, in shaded humid crevices, on sheltered soil banks, or on upturned bases of large old coniferous trees in moist forests, also on decorticated stumps, mosses and rocks World distribution: circumboreal to temperate in Euroasia and North America Sonoran distribution: Arizona. Notes: Chaenotheca furfuracea is characterized by having a green, farinaceous thallus, the yellow pruina of the ascomata, its long and slender ascomata, its spherical capitula and small spores. When poorly developed it is very similar to C. brachypoda, but differs in having a lighter mazaedium and a different ornamentation of the spores. Some authors other than Tibell continue to treat C. furfuracea under Coniocybe. When sterile, it may resemble Chrysothrix chlorina (that also contains vulpinic acid, but has a chlorococcoid photobiont), but is green rather than golden yellow or Psilolecia lucida (that contains rhizocarpic acid as the only major substance), but usually has yellow, unstalked apothecia..