Thallus effusus, endolithicus, medulla amyloidea. Apothecia superficiales, basi constricta, (0.8)1.0–1.4(2.0) mm diametro. Epihymenium brunneum. Ascosporae late ellipsoideae vel subgloboseae, 15.0–17.0 × 10.0–12.0 mm.
TYPE: FALKLAND ISLANDS. West Falkland, Mt Adam, UTM Grid 21F TC 8781, 670–700 m, feldmark on summit ridge, 25 January 1968, H. A. Imshaug 41048 & R. C. Harris (MSC, holotype; BCRU, E, HO, M, UPS, isotypes).
Description
Thallus effuse, immersed, rarely visible between grains of substratum (coarse sandstone), when visible creamy-white, without well developed cortex, a few brown pigmented cortical cells sometimes visible in microscopic section; usually covering relatively large areas (to 15–20 cm diam.). Medulla weakly IKI+ blue to red-purple. Photobiont chlorococcoid, cells (9–)12–15(–18) mm diam.
Apothecia scattered, black or dark brown, lecideine, superficial, strongly constricted at base, (0.8–)1.0–1.4(–2.0) mm diam., ±flexuose when mature; disc flat, usually white pruinose, more so when young, black or slightly brownish, brown when wet; proper margin black, persistent and slightly raised, 0.1 mm wide. In section: proper excipulum cupular, extending below hymenium and hypothecium as horizontally arranged, dark-brown pigmented hyphae, 170–250 µm high; laterally with ca 100 µm wide pale brown inner zone of radiating hyphae ca 3.5 µm wide and dark brown outer zone ca 80 µm wide composed of isodiametric cells 8–12 µm across. Interspersed with large groups of crystals clearly visible under polarized light. Hymenium hyaline, 120–135 mm tall; epihymenium brown, 12–20 mm wide; paraphyses 1.5–2.5 mm thick swelling at apex to 5.0 mm, with brown pigmented cap; simple, occasionally branched towards apex, septate, becoming moniliform toward apex, readily separating in water, IKI+ very pale purple. Asci cylindric, ca 85–100 × 17–20 mm, outer walls IKI+ blue, contents IKI+ red-brown, without tholus, Schaereria-type, dehiscing by simple split in outer wall; ascospores hyaline, 8/ascus, ±uniseriate in ascus, broadly ellipsoid to sub-globose (14.0–) 15.0–17.0(–20.0) × (8.5–) 10.0–12.0(–13.5) mm, length/breadth ratio 1.2–1.7. Hypothecium composed of randomly arranged hyphae, hyaline above, becoming pale to mid-brown below, 70–80 mm high, merging into the dark brown, horizontally arranged hyphae of excipulum that extends below hypothecium.
Conidiomata pycnidia, not frequent but usually present, black, immersed, 0.15–0.20 mm wide, walls dark brown; conidia simple, cylindric ca 3.5 × 0.8 mm, arising from elongate, simple, conidiogenous cells, Type II of Vobis (1980—Fig. 6).
Chemistry: Thallus and apothecia C–, K–, KC–, Pd–; unidentified fatty acid detected by TLC.
Distribution and ecology.Schaereria porpidioides is known only from the Falkland Islands. From the collection details it appears to be a species of exposed siliceous rocks. No vascular plants or bryophytes are present in the specimens and associated lichen species are few, but include Neuropogon fasciata (Du Rietz) Lamb, Pertusaria spegazzinii Müll. Arg., Poeltidea perusta (Nyl.) Hertel & Hafellner, and Rhizocarpon geographicum (L.) DC.