Metus D.J.Galloway & P.James
Type : Metus conglomeratus (F.Wilson) D.J.Galloway & P.James [Pilophoron conglomeratum F.Wilson]
Description : Thallus dimorphic Cladonia -like, primary thallus effuse, granular–crustose, glaucous-green to deep emerald-green on a thin to thick, pale to blackish prothallus. Podetia supporting ascomata without cups, erect to decumbent, to 1.5 cm tall and to 1–2 mm diam., hollow, terete or compressed, irregularly wrinkled or furrowed to longitudinally fissured or ±clathrate, simple, rarely furcate, subulate, covered with thalline granules to ±decorticate. Ascomata apothecia, terminal, hymenial discs brown to brown-black, ±globular and simple to clustered, convolute–conglomerate. Hymenium pale yellow-brown, 40–50 μm tall, I+ blue. Hamathecium of paraphyses, slender, simple, furcate or with interconnecting lateral anastomoses to 2 μm diam., slightly swollen (to 4 μm) at tips. Hypothecium deep red-brown, granular–opaque, K+ brownish, to 50 μm thick, I−. Asci cylindrical, tapering at foot, 35–40 × 5–8 μm; apical tholus prominent I+ dark-blue, 8-spored. Ascospores biseriate, simple, colourless, spindle-shaped or dacryoid, 8–10 (–14) × (2.5–)3–4(–4.5) μm. Conidiomata pycnidia, occasional to frequent, at apices of sterile, often decorticate podetia, or singly or clustered among thalline granules, minutely stalked, cylindrical, swollen or tapering at apices, mostly simple, rarely 2–3-branched, black or brown-black. Conidia colourless, falciform, 4–4.5 × 1 μm.
Metus [Latin for terror]. Named after H.M.S. Terror, one of the two ships of the Antarctic expedition of 1839–1843 commanded by Sir James Clark Ross, which visited New Zealand and Tasmania during the course of the expedition. Joseph Dalton Hooker (later Sir Joseph Hooker and the second Director of the Royal Botanic Gardens at Kew), assistant-surgeon to the expedition, collected many lichens from his landfalls in New Zealand, Tasmania and the Auckland and Campbell Is, and he also helped Thomas Taylor, Churchill Babington and William Mitten prepare these collections for publication. It is an austral genus of three species (Galloway & James 1987; Kirk et al. 2001) included in the family Cladoniaceae (Wedin et al. 2000a; Stenroos et al. 2002a; Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005), with two species being known from southern Chile, and one from New Zealand and SE Australia. All three species have a similar ecology and thrive in moist, humid conditions prevailing in stands of mature, primary or occasionally secondary forest, in areas of moderate to high rainfall. All are characteristic of markedly shaded habitats and many specimens collected are from rotting stumps and the basal plates or buttresses of large forest trees in the forest interior, where few other lichens are able to tolerate either reduced illumination or competition from bryophytes. The granular vegetative thallus of Metus develops on a pale or dark, arachnoid prothallus, and spreads over rotting or sometimes burned stumps, or covers pteridophyte rhizomes and/or fronds, e.g. the brush of tree ferns such as Alsophila, Dicksonia and Sphaeropteris, bryophytes or litter, investing these substrata with a thick green crust. For additional data on the genus see Galloway & James (1987) and Kantvilas (1992a).
