Chroodiscus lamelliferus
Description : Thallus thin, effuse, 40–100 μm thick, continuous, rather uneven, following surface of substratum, green, greyish green to grey-white, without a prothallus. Photobiont green, Trentepohlia. Apothecia scattered, at first immersed in ±subglobose, irregularly cracked and sculptured thalline warts, erumpent at maturity, rounded, 1–2.5(–3) mm diam., 0.3–1 mm high, adnate to slightly constricted at base, rarely semi-immersed; disc plane, smooth, subundulate to slightly wrinkled, orange-pink to brownish pink, epruinose or faintly white-pruinose, sometimes obscured by adhering fragments of excipulum, but more commonly widely exposed and frequently eroded in older fruits; thalline margins and excipulum whitish, Geaster- like, at first incurved and obscuring disc, becoming erect to recurved, irregularly radially and tangentially fissured, exfoliating, forming several layers of fractured lamellae. Hypothecium yellow-brown to brown, K+ orange-yellow, intensifying, 40–80(–160) μm thick, with a hyaline medullary layer below, 60–120 μm thick, K−, I+ faint pinkish. Hymenium colourless, 140–180 μm tall; epithecium granular, pale-brown, 10–20(–40) μm thick. Asci cylindrical-clavate, 150–160 × 26–42 μm. Ascospores ellipsoidal, colourless, straight to slightly curved, thinly halonate, densely muriform, 38–70 × (10–)13–22 μm, with 50–70 thin-walled cells, 2–3 μm diam., irregularly arranged.
Chemistry : Medulla and apothecial margins K± dirty-brown, C−, KC−, Pd+ red, UV−; containing succinprotocetraric, fumarprotocetraric and protocetraric acids.
N: Wellington (York Bay). S: Nelson (NW Nelson; Rough Creek N of Lewis Pass). On bark or amongst bryophytes on rotting logs in moderate to deep shade, associating with Parmeliella nigrocincta and Psoroma asperellum; still very poorly collected in New Zealand. Also known from Tasmania where it colonises peaty soil and rock crevices in moorland and alpine vegetation, as well as bark (Kantvilas & Vězda 2000: 338–339; McCarthy 2003c, 2006).
Australasian
Illustration : Kantvilas & Vězda (2000: 337, fig. 5).
Chroodiscus lamelliferus is characterised by: the large apothecia (to 2.5 cm diam.) with exposed discs and exfoliating, fissured margins; densely muriform ascospores, 38–70 × (10–)13–22 μm, with 50–70 thin-walled cells, 2–3 μm wide, irregularly arranged in spore; and compounds of the protocetraric acid chemosyndrome.
