Introduction
The lichen genus Placopsis (Trapeliaceae) is a common component of high-rainfall, temperate biomes in southern South America with 18 species currently known from the region (Galloway Reference Galloway2002). This is undoubtedly a rather low estimate of potential species numbers, especially when a more closely studied area comprising broadly similar biomes, such as New Zealand, discloses more than twice that number of taxa (Galloway Reference Galloway2007, Reference Galloway2008; D. J. Galloway, unpublished). Collections of Placopsis made by Prof. Henry Imshaug (East Lansing) from remote locations in the West Patagonian channels, during cruise 69–4 of R/V Hero (see Imshaug Reference Imshaug1970: 41, fig. 1, for collecting localities) from 18 September to 10 October 1969, and held in the herbarium of Michigan State University (MSC), together with gatherings from southern Chile and Argentina, made by other collectors (Profs A. Elvebakk, W. Quilhot and U. Søchting), yielded four additional taxa for southern South America: Aspiciliopsis macrophthalma (Hook. f. & Taylor) B. de Lesd., Placopsis fusciduloides D. J. Galloway, P. gelidioides Du Rietz ex I. M. Lamb and P. tararuana (Zahlbr.) D. J. Galloway. New records of 13 species of Placopsis are reported for the region, supplementing and extending the information in Galloway (Reference Galloway2002). Placopsis imshaugii D. J. Galloway, a new Magellanic species, is described elsewhere. A revised key to the Placopsis mycobiota of southern South America, including Juan Fernández, is included as a stimulus to further collection and study of Placopsis in the region.
Materials and Methods
The study was based on material obtained from the following herbaria: CANB, GB, MSC, UV. Thin-layer, and high-performance liquid chromatography were carried out according to standardized methods (Culberson Reference Culberson1972; Feige et al. Reference Feige, Lumbsch, Huneck and Elix1993).
Species new to southern South America
Aspiciliopsis macrophthalma (Hook. f. & Taylor) B. de Lesd
in Ann. Cryptog. Exot. 4 (2): 101 (1930) [as “macrophtalma” (sic.)].—Urceolaria macrophthalma Hook. f. & Taylor, Lond. J. Bot. 3: 649 (1844).—Lecanora macrophthalma (Hook. f. & Taylor) Nyl., Mém. Soc. Imp. Sci. Nat. Cherbourg 5: 336 (1858).—Placopsis macrophthalma (Hook. f. & Taylor) Nyl. in J. M. Crombie, J. Bot. 15: 106 (1877).—Placodium macrophthalmum (Hook. f. & Taylor) Müll. Arg., Bot. Jahrb. 5: 135 (1884); type: Kerguelen [“Kerguelen's Land”], Christmas Harbour, on hills, 1–700 ft, J. D. Hooker 707 (BM 8108!—lectotype [fide Dodge (Reference Dodge1948: 175)]; BM 8105!—isolectotype).
Remarks. Aspiciliopsis macrophthalma is an austral species, characterized by: a thick (0·15–0·50 mm), spreading, tartareous, creamish or pale whitish pink to greyish buff thallus, which is ± continuous to irregularly cracked, the cracks sharp-edged, 0·05–0·1 mm wide; the surface is minutely roughened, here and there minutely white-pruinose, and ± minutely papillate appearing maculate (×10 lens) in places; immersed, aspicilioid apothecia 0·5–1·0 (–1·5) mm diam., the disc pale to dark red-brown, to somewhat blackish shallowly to deeply urceolate, the thalline margins well delimited, concolorous with the thallus and separated from it by cracks; immersed, irregularly cracked cephalodia, merging gradually into the thallus at their margins, and distinguished from the thallus only by their colour (dark purple-blue when wet, concolorous with the thallus or darker to ± pinkish when dry) and texture; a colourless hymenium (150–300 µm tall); broadly ellipsoidal, colourless ascospores, uniseriate in the ascus, (15–)20–25(–30) × 12–15(–17) µm; and long, filiform conidia, 40–60 × 1 µm.
In a recent molecular study, Schmitt et al. (Reference Schmitt, Lumbsch and Søchting2003) showed that Placopsis macrophthalma (the generitype of Aspiciliopsis) is more closely related to Orceolina than it is to Placopsis. Accordingly, they proposed the resurrection of Aspiciliopsis as an independent monospecific genus, a view that is followed here.
Chemistry. 5-O-methylhiascic acid (major), gyrophoric acid (minor), hiascic acid (minor) and lecanoric acid (minor).
Ecology and distribution. Aspiciliopsis macrophthalma occurs widely in the Southern Oceans, being known from Îles Kerguelen (Hooker & Taylor Reference Hooker and Taylor1844; Hooker Reference Hooker and Hooker1847; Tuckerman Reference Tuckerman1875; Crombie Reference Crombie1876, Reference Crombie1877; Bouly de Lesdain Reference Bouly de Lesdain1931; Lamb Reference Lamb1947; Dodge Reference Dodge1948, Reference Dodge1966; Imshaug Reference Imshaug and Llano1977), St Paul Island (Nylander Reference Nylander1886), Heard Island and Îles Crozet (Dodge Reference Dodge1948; Dodge & Rudolph Reference Dodge and Rudolph1955; Øvstedal & Gremmen Reference Øvstedal and Gremmen2006), Marion and Prince Edward Islands (Ott et al. Reference Ott, Przewosnik, Sojo and Jahns1997; Øvstedal & Gremmen Reference Øvstedal and Gremmen2001) and southern New Zealand (Galloway Reference Galloway2007, Reference Galloway2008; D. J. Galloway, unpublished).
Specimen examined. Chile: XII Región: moorland in gap at head of fiord E of Monte Roberto, Isla Madre de Dios, 50°20′S, 75°21′W, 29.ix.1969, H. A. Imshaug 44151 & K. Ohlsson (CANB 006777508).
Placopsis fusciduloides D. J. Galloway
in Australas. Lichenol. 57: 16 (2005); type: New Zealand, South Island, Otago, Humboldt Mountains, around Lake Nerine, Mt Aspiring National Park, on rock and moss in open alpine herbfield with Celmisia, Aciphylla, Anisotome, 1500 m, 6 ii 1999, A. Knight s. n. (OTA 058063!—holotype; CHR 528307!—isotype).
Remarks. Placopsis fusciduloides is an austral species characterized by: an orbicular to spreading, closely attached thallus with neatly pleated, flat to subconvex, flabellate margins, without a marginal prothallus; flattish to subconvex lobes, areolate-cracked centrally but discrete to contiguous at or near the margins; a ± continuous, thin, velvety, pruina (×10 lens), concolorous with upper surface or pale grey-brown; distinctively eroding soralia with a well-defined, raised margin and pale greenish white or white, coarsely granular to pseudoisidiate soredia; spreading, plicate-ridged to deeply eroded cephalodia developed in concentric lines or bands near the thallus centre; scattered, often rather rare, sessile apothecia, 0·5–1·5(–2) mm diam., scattered (when present) amongst cephalodia; hymenium 115–140 (–160) µm tall; ascospores broadly ellipsoid to subglobose, 15–20 × 8·5–11·5(–15) µm; filiform, shallowly arcuate conidia, 15–22 × 0·5 µm.
Chemistry. Gyrophoric acid (major), ± cryptostictic acid (major), lecanoric acid (minor), 5-O-methylhiascic acid (minor trace), hiascic acid (minor or trace), ± 2′-O-methylhiascic acid (trace), ± stictic acid (minor) and ± connorstictic acid (minor).
Ecology and distribution. In southern South America Placopsis fusciduloides is found on coastal rocks and on rocks in scrub and grassland from 30–1000 m. Elsewhere it grows on rock outcrops, or on peaty soil or over mosses on soil in exposed subalpine to high-alpine grassland and in open, alpine herbfield. It has an altitudinal range of 610–2002 m in New Zealand, and is known from 4250 m in Bolivia (Galloway Reference Galloway2005). Elsewhere P. fusciduloides is known from New Zealand, Canada (British Columbia), and Bolivia (Galloway Reference Galloway2005, Reference Galloway2007; D. J. Galloway, unpublished).
Specimens examined. Chile: Juan Fernández Archipiélago: Más Afuera, Campo Correspondencia, large scattered specimens of Lophosoria in grassland at E base of Cerro Correspondencia, 1000 m, 1965, H. A. Imshaug 36983, 36988, 37002, 37006, 37043, 37054 (MSC; CANB); Más a Tierra, Frances Valley, W side of valley on lateral ridge of Cordón de los Chifladores, 370 m, 1965, H. A. Imshaug 38019 (MSC); Bahía Cumberland, Convict Caves, in open at mouth of caves, 30 m, 1965, H. A. Imshaug 38246 (MSC); Cordón Salsipuedes, scrub on exposed ridge, 600 m, 1965, H. A. Imshaug 38135 (MSC). Región XII: Península Brunswick, Puerto Cutter, along shore N of copper mine, 1967, H. A. Imshaug 39413B & R. C. Harris (MSC); ibid., Puerto del Hambre, Nothofagus forest, Fuerte Bulnes, Punta Santa Ana, 1967, H. A. Imshaug 38770 & R. C. Harris (MSC).—Argentina: Tierra del Fuego: Isla Grande, 54°51′S, 68°35′W, Parque Nacional de Tierra del Fuego, open meadow and scrub on low hills on W side of Bahía Lapataia near Chilean frontier, 1971, H. A. Imshaug 55054 & K. Ohlsson (MSC).
Placopsis gelidioides Du Rietz ex I. M. Lamb
in Lilloa 13: 210 (1947); type: New Zealand. Canterbury, Cass, Mt Misery in upper subalpine belt, 1926, G. Einar & Greta Du Rietz 1468:15 (S!—holotype; UPS!—isotype [1468: 14]).
Remarks. Placopsis gelidioides is characterized by: convex, areolate-cracked lobes, often arranged in contiguous parallel lines, very thick swollen, smooth, thalline margins to the disc; brownish often deeply cracked disc; a pale pinkish or pale yellowish brown, nubilated hymenium, 175–200 µm tall; ellipsoidal ascospores uniseriate in ascus, contents vacuolate with 2–3(–4) prominent vacuoles, (15–)16·5–18·5(–20) × 8–10 (–11·5) µm; and filiform, curved conidia, 16–20 × 0·5 µm.
Chemistry. 5-O-methylhiascic acid (major), gyrophoric acid (submajor), lecanoric acid (minor) and hiascic acid (minor) [J. A. Elix, personal communication].
Ecology and distribution. Placopsis gelidioides, formerly considered a New Zealand endemic (Galloway Reference Galloway2007) is an austral, alpine species that is only infrequently collected. Its ecology in both New Zealand and southern Chile is still very incompletely known.
Specimens examined. Chile: IX Región: Parque Nacional Nahuelbuta, 29 v 1970, J. Redón s. n. (UV 2163). XI Region: Sector Húngaro, Parque Nacional Tamango, Cochrane, 47°11′S, 72°28′W, 400m, v 2001, T. Ormeño s. n. (UV 3553)
Placopsis tararuana (Zahlbr.) D. J. Galloway
in Bibl. Lichenol. 78: 59 (2001).—Lecanora (Placopsis) tararuana Zahlbr., Denkschr. Akad. Wiss. Wien math.-maturwiss Kl. 104: 348 (1941); type: New Zealand, [Wellington], “on rock in forest, Table Top, Tararua Mountains, North Island”, c. 800 m. Sept. 1933, E. Chamberlain 189 (W 696!—holotype).
Remarks. Placopsis tararuana is characterized by: a thin, crustose dark green thallus which is continuous to minutely and irregularly effigurate-cracked; the round to oval ±immersed cephalodia, delimited by a ± continuous crack and having a plane to minutely lumpy or wrinkled surface, never or only rarely plicate-ridged or furrowed, not radiate-cracked; the small, scattered, sessile apothecia with verrucose thalline exciple (noticeable below discs); and by the oval to broadly ellipsoid ascospores, 20–25 (–26·5) × 10–12·5 µm. It is distinguished from Aspiciliopsis macrophthalma, by differences in colour and thickness and surface features of the thallus, and by major differences in the morphology of the cephalodia (those of A. macrophthalma are irregularly and deeply cracked, and merge gradually into the thallus at their margins, in contrast those of P. tararuana are delimited from the thallus by a ± continuous gaping crack, and the upper surface is continuous, plane to minutely wrinkled and without deep radiating cracks). The apothecia of A. macrophthalma aredistinctively immersed-aspicilioid, whereas those of P. tararuana are sessile. Ascospores of both A. macrophthalma and P. tararuana are oval to broadly ellipsoidal and of similar dimensions. A full description is given in Galloway (Reference Galloway2007: 1283–1284).
Chemistry. Gyrophoric acid (major), lecanoric acid (minor) and 5-O-methylhiascic acid (trace) [J. A. Elix, personal communicaton].
Ecology and distribution. Placopsis tararuana is an austral species known mainly from New Zealand, principally from South Island, where it occurs close to or west of the Main Divide (Galloway Reference Galloway2007; D. J. Galloway, unpublished) in high-rainfall areas and commonly on rocks in beech (Nothofagus) forest.
Specimens examined. Chile: XI Región: 50°22′S, 75°20′W, scrub-moorland mosaic on hill behind mine. Bahía Corbeto Papudo, 1969, H. A. Imshaug 44091 & K. Ohlsson (MSC); ibid., 49°49′S, 75°16′W, scrub along river and edge of forest, fiord W of Mte Markham, Pto Alert, 1969, H. A. Imshaug 43952 & K. Ohlsson (MSC).
New records of Placopsis from southern South America
Placopsis baculigera I. M. Lamb
Remarks. Placopsis baculigera is a distinctive species with rusty orange convex lobes, having very prominent, swollen thalline margins to the apothecia, a glossy, epruinose disc and rod-shaped rather than filiform conidia (Lamb Reference Lamb1947; Galloway Reference Galloway2002). Formerly known from several localities in Chile and thought to be a Chilean endemic (Galloway Reference Galloway2002), it is here reported for the first time from Argentina.
New Records. Argentina: Tierra del Fuego: Isla Grande, 54°42′S, 67°473′W, krummholz region on W side of Paso Garibaldi, Sierra Alvear, 460 m, 1971, H. A. Imshaug 54822 & K. Ohlsson (MSC); ibid., 54°43′S, 68°07′W, alpine region on summit of mountain to the E of Monte Olivia, Sierra de Sorondo, 970 m, 1971, H. A. Imshaug 55585 & K. Ohlsson (MSC).
Placopsis bicolor (Tuck.) B. de Lesd
Remarks. Placopsis bicolor is characterized by: rusty-orange convex lobes that are never sorediate; prominent, swollen margins to the apothecia; a glossy, epruinose disc; and filiform conidia. Full descriptions are given in Galloway et al. (Reference Galloway, Lewis-Smith and Quilhot2005: 325) and Galloway (Reference Galloway2007: 1237).
Placopsis bicolor is an austral species, known from Îles Kerguelen, Îles Crozet, Heard Island, Marion Island, South Georgia, southern South America and southern New Zealand (Lamb Reference Lamb1947; Dodge Reference Dodge1948, Reference Dodge1966; Dodge & Rudolph Reference Dodge and Rudolph1955; Lindsay Reference Lindsay1977; Galloway Reference Galloway2002, Reference Galloway2007; D. J. Galloway, unpublished; Galloway et al. Reference Galloway, Lewis-Smith and Quilhot2005; Øvstedal & Gremmen Reference Øvstedal and Gremmen2006, Reference Øvstedal and Gremmen2007).
New Records. Chile: XII Región: 50°01′S, 74°42′W, moorland and scattered outcrops E of Pta Brown, Pto Charrúa, 1969, H. A. Imshaug 43586 & K. Ohlsson (CANB); 50°03′S, 75°02′W, mossy forest near E shore of Isla Pilot (Pto del Morro), 1969, H. A. Imshaug 44713 & K. Ohlsson (CANB); 50°03′S, 75°02′W, open hillside with outcrops, W side of Isla Grant (Pto del Morro), 1969, H. A. Imshaug 44709 & K. Ohlsson (CANB); Península Brunswick, Puerto Cutter, along shore N of copper mine, 1967, H. A. Imshaug 39396, 39415, & R. C. Harris (MSC).
Placopsis cribellans (Nyl.) Räsänen
Remarks. Placopsis cribellans is characterized by: rather small, neat, rosette-forming to irregularly spreading, closely appressed thalli without a projecting prothallus; convex, rather narrow lobes that are contiguous to slightly separate from the margins to centre; a pale green to green-brown upper surface when moist, grey-white to fawnish or grey-brown when dry, usually darkening towards apices of lobes, with occasional to frequent, scattered white maculae (×10 lens), best seen when moist, smooth, glossy to matt, frequently pitted or punctate with minute scars or depressions from abrading isidia, without soredia or pruina; globose isidia, 0·1 mm diam. or less, scattered to densely crowded, easily abraded and leaving whitish to dark grey-green or blackened pits; mainly central cephalodia that are flattened-plicate, rarely white-pruinose; rather small, solitary, sessile apothecia with swollen, thick margins and urceolate to flat, white or grey-pruinose discs; and ellipsoidal ascospores, (12–) 14–16·5(–18·5) × (5–)6–9 µm.
Placopsis cribellans is a widespread, cosmopolitan species known from Japan, Korea, Taiwan, Hawaii, Papua New Guinea, Australia, the Galápagos, Tristan da Cunha, the Aleutian Islands, British Columbia, Chile, Argentina and New Zealand (Lamb Reference Lamb1947; Galloway Reference Galloway1985, Reference Galloway2002, Reference Galloway2007; D. J. Galloway, unpublished; Brodo et al. Reference Brodo, Noble, Ahti and Clayden1987; Aptroot & Sipman Reference Aptroot and Sipman1991; Smith Reference Smith and Galloway1991; Brodo Reference Brodo1995; Elix & McCarthy Reference Elix and McCarthy1998; McCarthy Reference McCarthy2010).
New Records. Chile: Juan Fernández Archipiélago: Más Afuera, Campo Correspondencia, large scattered specimens of Lophosoria in grassland at E base of Cerro Correspondencia, 1000 m, 1965, H. A. Imshaug 37041 (MSC ); Más a Tierra, Tres Puntas 200 m, 5 i 1917, Carl & Inge Skottsberg s. n. [“Svenska Pacific Expeditionen 1916–1917”](GB) [determined by Zahlbruckner as “L. gelida f. leprosula Zahlbr.”, and by Lamb as “P. fuscidula f. leprosula + P. cribellans” – I.M.L. 1/1947]. XII Región: Península Brunswick, Puerto Cutter, along shore N of copper mine, 1967, H. A. Imshaug 39396 & R.C. Harris (MSC).—Argentina: Tierra del Fuego: Isla Grande, 54°51′S, 68°35′W, Parque Nacional de Tierra del Fuego, open meadow and scrub on low hills on W side of Bahía Lapataia near Chilean frontier, 1971, H. A. Imshaug 554038, 55054 & K. Ohlsson (MSC).
Placopsis dusenii I. M. Lamb
Remarks. Placopsis dusenii is characterized by: a thick, tartareous, closely attached, smooth, greenish white to pinkish, distinctively areolate thallus without a marginal prothallus; angular to irregular areolae, 0·5–3(–4·5) mm diam., separated by deep cracks 0·2–1·0 mm wide and appearing as distinctive ‘islands’ (× 10 lens), and lack of isidia, pustules, pruina and soredia. The surface of each areola is distinctively minutely cerebriform (×10 lens). Cephalodia are attached to areolae or discrete, separated by deep cracks, pale pinkish when dry, purplish when wet, level with the thallus surface or spreading very slightly above the surface. The apothecia are scattered, rather rare, somewhat immersed to ± sessile, (0·1–)0·5–1·0(–1·2) mm diam., solitary or 4 or 5 together, rounded to contorted through mutual pressure, margins swollen, prominent, 0·1–0·2 mm thick, glossy, smooth to subcrenulate, concolorous with thallus; the disc is pale to dark red-brown, plane to concave, epruinose. The hymenium is 130–250(–300) µm tall. Ascospores are broadly ellipsoidal, 17·5–22·5 ×(9–)10–12·5 µm. Conidia are filiform, 18–21 × 0·5–1 µm.
Placopsis dusenii is an austral species still only rarely collected in southern Chile and known also from southern New Zealand and Campbell Island (Galloway Reference Galloway2002, Reference Galloway2007; D. J. Galloway, unpublished), and Îles Kerguelen (D. J. Galloway, unpublished).
New Records. Chile: XI Región: 48°04”S, 74°38′W, moorland on ridge, Puerto Island (Península Swett), 1969, H. A. Imshaug 43249 & K. Ohlsson (MSC); ibid., 50°01′S, 74°42′W, moorland and scattered outcrops E of Pta Brown, Pta Charrúa, 1969, H. A. Imshaug 43597 & K. Ohlsson (MSC).
Placopsis fuscidula I. M. Lamb ex Räsänen
Remarks. Placopsis fuscidula is characterized by: closely attached, orbicular to spreading thalli, 2–5(–7) cm diam., without a prothallus; slightly swollen marginal lobes; pale greenish white or olivaceous upper surface when moist, pale creamish, ivory to pale brownish pink or greyish blue when dry, smooth, matt or occasionally glossy at or near the margins, commonly with a fine greyish to grey-white pruina (×10 lens), giving the surface a finely velvety appearance; absence of isidia, maculae, pseudocyphellae or soredia; scattered, sessile apothecia, solitary or 2–3–together, rounded to subirregular through mutual pressure, 0·5–1·5(–2) mm diam., the thalline margins thick at first and almost obscuring the disc, to ± excluded at maturity, concolorous with the thallus, smooth, entire, thinly white-pruinose; discs that are concave at first, becoming plane to subconvex, pale to dark red-brown, translucent when moist, smooth to minutely papillate, with or without a fine, white pruina; a colourless hymenium (150–)170–200(–225) µm tall; ellipsoidal ascospores 17·5–22·5(–25) ×(9–)10–12·5 µm; and filiform conidia, curved to straight, 17–21 × 0·5–1 µm.
Placopsis fuscidula is an austral species known from Venezuela (Follmann Reference Follmann1973) southern Chile, Juan Fernández, Tristan da Cunha New Zealand (Lamb Reference Lamb1947; Jørgensen Reference Jørgensen1979; Galloway Reference Galloway2002, Reference Galloway2007; D. J. Galloway, unpublished) and Îles Kerguelen (D. J. Galloway, unpublished).
New Records. Chile: Juan Fernández Archipiélago: Más Afuera, Campo Correspondencia, large scattered specimens of Lophosoria in grassland at E base of Cerro Correspondencia, 1000 m, 1965, H. A. Imshaug 37037, 37046, 37048, 37052 (MSC); Los Inocentes, south summit, heath with Lophosoria, 1300 m, 1965, H. A. Imshaug 37381, 37402A (MSC); Casatales, 1100–1140 m, 5 iii 1917, Carl & Inge Skottsgberg s. n. [“Svenska Pacific Expeditionen 1916–1917”] (GB) [determined by Zahlbruckner as “Lecanora patagonica f. sorediosula Zahlbr.”]; Hochplateau, St. 26, c. 1150 m, 25 ii 1917, Carl & Inge Skottsberg s. n. [“Svenska Pacific Expeditionen 1916–1917”] (GB) [determined by Zahlbruckner as “Lecanora (Placopsis) gelida f. leprosula Zahlbr., and Lecanora (Placopsis) patagonica f. sorediosula Zahlbr.”]. XII Región: Isla Desolación, 53°04′S, 73°56′W, mossy forest near W shore of Fondeadero Nassau, Pto Churruca, 1969, H. A. Imshaug 49854 & K. Ohlsson (MSC).
Placopsis gelida (L.) Linds
Remarks. Placopsis gelida is a cosmopolitan species, characterized by: neat rosettes with well-defined, slightly swollen, plicate margins free of prothallus; a matt to shining, somewhat polished and ivory-like upper surface with occasional patches of pruina; large central, deeply plicate cephalodia without pruina; eroding soralia generally delimited by a sharply-defined and slightly raised margin, either scattered and discrete to confluent and covering much of the thallus; farinose greenish to green-grey soredia; rather rare, scattered, sessile apothecia with a vivid red-pink disc, with or without a whitish pruina; a poorly developed thalline margin of farinose granules; broadly ellipsoidal to subglobose ascospores, (13·5–)18–23·5(–25) × 8·5–12(–15) µm; and a chemistry of gyrophoric and hiascic acids.
Placopsis gelida is a cosmopolitan species discussed in Lamb (Reference Lamb1947), Coppins & James (Reference Coppins and James1984), Moberg & Carlin (Reference Moberg and Carlin1996) andGalloway (Reference Galloway2007; D. J. Galloway, unpublished).
New Records. Chile: Juan Fernández Archipiélago: Más Afuera, Correspondencia Torres, 1360 m, 14 ii 1917, Carl & Inge Skottsberg s. n. [“Svenska Pacific Expeditionen 1916–1917”] (GB); Casatales, 1100 –1140 m, 5 iii 1917, Carl & Inge Skottsberg s. n. [“Svenska Pacific Expeditionen 1916–1917”] (GB) [determined by Zahlbruckner as “Lecanora patagonica f. sorediosula Zahlbr.”].
Placopsis microphylla (I. M. Lamb) D. J. Galloway
Remarks. Placopsis microphylla is characterized by: small flattened squamules with a central, white-pruinose spot (×10 lens); shallowly eroding, vesicular-excavate soralia, with a sharply defined and often elevated margin, exposing green, granular soredia; pale pink apothecia with elevated papillae around the margins; a colourless hymenium,169–180 µm tall; broadly ellipsoidal ascospores, uniseriate in the ascus, 21·5–27(–30) × 13·5–15 µm, contents granular, vacuolate, pinkish when fresh, scattered, immersed, mainly central pycnidia, ostiole 0·08–0·12 mm diam., dark brown, papillate to punctiform; and filiform, straight or slightly curved conidia, 8·5–11·5(–12) × 1 µm.
Placopsis microphylla is an austral species known from Argentina and Chile in southern South America (Lamb Reference Lamb1947; Galloway Reference Galloway2002), and also from Australia (Louwhoff et al. Reference Louwhoff, Gibson and Elix1997), and New Zealand (Galloway Reference Galloway2007; D. J. Galloway, unpublished).
New Records. Chile: XII Región: 50°22′S, 75°20′W, limestone dome on summit of mountain behind mine, Bahía Corbeta Papudo, 1969, H. A. Imshaug 44094 & K. Ohlsson (MSC); ibid., 53°51′S, 71°07′W, grassy area, W shore of Bahía San Nicolás, 1969, H. A. Imshaug 45618 & K. Ohlsson (MSC).
Placopsis parellina (Nyl.) I. M. Lamb
Remarks. Placopsis parellina is characterized by: a small, spreading thallus of contiguous to overlapping squamules (when growing on soil), or flattened and rosette-forming (when growing on rock); absence of isidia or soredia; scattered, flattened to subhemispherical cephalodia 0·5–1·2 mm diam., that are minutely plicate-striate to smooth and sometimes almost immersed in thalline squamules; sessile apothecia (0·2–)0·5–2(–2·5) mm diam., with a prominent, swollen, Ochrolechia-like thalline margin, concolorous with the thallus; a pale to dark red-brownor brown-black, epruinose disc; a colourless hymenium, 200–240 µm tall; and broadly ellipsoidal ascospores, 16–20(–25) × (8·5–)10–15 µm.
Placopsis parellina is endemic to South America (Galloway Reference Galloway2002; Galloway & Arvidsson Reference Galloway and Arvidsson2007), where it is known from Ecuador to southern Chile. It is recorded here for the first time from Juan Fernández.
New records. Chile: Juan Fernández Archipiélago: Más Afuera, Ad Campo Correspondencia, St. 26, 1130 m, 25 ii 1917, Carl & Inge Skottsberg s. n. [“Svenska Pacific Expeditionen 1916–1917”] (GB) [determined by Zahlbruckner as “Lecanora (Placopsis) gelida”, and by Lamb as “P. parellina v. rhodocarpa” – I.M.L. 1/1947]; Más a Tierra, stark erodierten Boden in unter Teil als Kolonia-Tals, 1916, Carl & Inge Skottsberg 328 [“Svenska Pacific Expeditionen 1916–1917”] (GB) [determined by Zahlbruckner as “Lecanora (Placopsis) argillacea f. rhodophthalma” and by Lamb as “P. parellina var. rhodocarpa” – I.M.L. 1/1947].
Placopsis perrugosa (Nyl.) Nyl
Remarks. Placopsis perrugosa is characterized by: closely appressed thalli forming neat rosettes to irregularly spreading and coalescing patches, 1–10(–15) cm diam.; marginal lobes that are discrete, often furcate or divergent, flattened; and a distinctive upper surface that is shallowly verrucose-areolate resembling snakeskin. A full description of the species is given in Galloway (Reference Galloway2002: 95).
Placopsis perrugosa is a widespread austral species being known from southern South America, (where it occurs in both Argentina and Chile from lat. 37°S to lat. 55°S), Australia, Papua New Guinea, New Ireland, the Galápagos Islands, the Falkland Islands, Gough Island, Tristan da Cunha and New Zealand (Lamb Reference Lamb1947; Galloway Reference Galloway2002, Reference Galloway2007;D. J. Galloway, unpublished; McCarthy Reference McCarthy2010).
New records. Chile: XII Región: Isla Desolación, 52°51′S, 74°28′W, Hebe scrub along S shore of Caleta San José, Bahía Tuesday, 1969, H. A. Imshaug 44738 & K. Ohlsson (MSC); Península Brunswick, rock in tidal pool, Seno Otway, Nothofagus and Drimys forest at Bahía Camden, H. A. Imshaug 39069 & R. C. Harris (CANB).—Argentina: Tierra del Fuego: Isla Grande, 54°51′S, 68°35′W, Parque Nacional de Tierra del Fuego, open meadow and scrub on low hills on W side of Bahía Lapataia, near Chilean frontier, 1971, H. A. Imshaug 55029, 55058 & K. Ohlsson (MSC); 54°45′S, 68°13′W, cut-over and grazed area at base of cliffs on W side of Río Olivia Valley (W of Monte Olivia), along Ruta Nacional No. 3, 120 m, 1971, H. A. Imshaug 55265 & K. Ohlsson (MSC).
Placopsis pycnotheca I. M. Lamb
Remarks. Placopsis pycnotheca is characterized by: a crustose, spreading thallus of swollen warts or squamules, encrusting sand, soil and small pebbles; simple, subglobose to finger-like isidia; scattered, subpedicellate apothecia with swollen thalline margins and roughly papillate to irregularly cracked discs; elongate-ellipsoidal ascospores, (15–)18–24 × (6–)7–9(–10) µm; and filiform conidia, 16–20 × 0·5 µm.
Placopsis pycnotheca is known from Argentina and from the VII to XII Regións of Chile (Galloway Reference Galloway2002). It is reported here for the first time from Juan Fernández.
New records. Chile: Juan Fernández Archipiélago: Más Afuera, Los Inocentes, south summit, heath with Lophosoria, 1300 m, 1965, H. A. Imshaug 37389, 37415B (MSC); Campo Correspondencia, large, scattered specimens of Lophosoria in grassland at east base of Cerro Correspondencia, 1000 m, 1965, H. A. Imshaug 36991, 37006 (MSC; CANB).
Placopsis rhodocarpa (Nyl.) Nyl
Remarks. Placopsis rhodocarpa is characterized by: a dark green to pale greenish to whitish placodioid thallus; small, scattered, capitate soralia with granular, green soredia; flat, pink, delicately wrinked-folded to radially cracked cephalodia; scattered thick-margined Ochrolechia-like apothecia with rose-pink to red-brown, epruinose discs; and ellipsoidal ascospores, (16·5–) 18–20 ×6·5–10 µm. It is a rather variable species exhibiting a range of morphologies depending on whether its substratum is clayey soil or rock, and also on the degree of exposure of the substratum.
Placopsis rhodocarpa is an austral species known from Ecuador (Galloway & Arvidsson Reference Galloway and Arvidsson2007), Bolivia (Nylander Reference Nylander1861; Lamb Reference Lamb1947; Galloway Reference Galloway2002), the VIII Región of Chile (Galloway Reference Galloway2002), Australia (McCarthy 2010), and New Zealand (Galloway Reference Galloway2007; D. J. Galloway, unpublished). It is reported here for the first time from Juan Fernández.
New records. Argentina: Tierra del Fuego: Isla Grande, 54°45′S, 68°13′W, cut-over and grazed area at base of cliffs on W side of Río Olivia Valley (W of Monte Olivia), along Ruta Nacional No. 3, 120 m, 1971, H. A. Imshaug 55265 & K. Ohlsson (MSC).—Chile: Juan Fernández Archipiélago: Más Afuera, Correspondencia Torres, 1360 M, 14 ii 1917, Carl & Inge Skottsberg s. n. [“Svenska Pacific Expeditionen 1916–1917”] (GB); Más a Tierra, Tres Puntas 200 m, 5 i 1917, Carl & Inge Skottsberg s. n. [“Svenska Pacific Expeditionen 1916–1917”] (GB) [determined by Zahlbruckner as “L. gelida f. leprosula Zahlbr.”, and by Lamb as “P. fuscidula f. leprosula + P. cribellans” – I.M.L. 1/1947].
Placopsis roivainenii I. M. Lamb
Remarks. Placopsis roivainenii is a distinctive lichen characterized by: a tartareous, crustose, rosette-forming thallus (0·5–1 mm thick), with plicate-effigurate margins that are ±continuous or intersected by narrow cracks (but not forming discrete lobes) and that is areolate centrally, the areolae cut off by deep and often gaping cracks; a continuous, smooth pale grey-white upper surface, that is patchily minutely scabrid or white-pruinose, the pruina often glistening (×10 lens); sparse, central large, radiate-plicate cephalodia (1–9 mm diam.), sometimes developing in arcs or circles and secondarily recolonized by thalline tissue; scattered, sessile apothecia with thick, inrolled thalline margins, and a pale pinkish to red-brown disc that becomes irregularly and deeply fissured, minutely roughened-papillate and thinly buff-pruinose; a colourless hymenium 180–225 µm tall; ellipsoidal ascospores, 18–20 × 9–10·5 µm; and filiform, curved, conidia, 18–24 × 0·5 µm.
Placopsis roivainenii appears to be endemic to Chile (Galloway Reference Galloway2002: 98) where it grows on rocks in mainly coastal areas between latitudes 40°S and 55°S.
New Record. Chile: XI Región: 48°04”S, 74° 38′W, moorland on ridge, Puerto Island (Península Swett), 1969, H. A. Imshaug 43249 & K. Ohlsson (MSC).
Placopsis subcribellans (I. M. Lamb) D. J. Galloway
Remarks. Placopsis subcribellans is an austral species characterized by: neatly orbicular, closely attached thalli, with continuous, flat, scalloped margins; a glossy upper surface (resembling polished ivory) that is continuous to incised with radiating, narrow cracks; subglobose to flattened isidia developing along cracks in the upper surface; shallowly hemispherical cephalodia that are mainly central or developed in concentric arcs; rather sparse, sessile apothecia with pale pinkish to rusty-brown, roughened-papillate to cracked discs, with or without a fine, white pruina; a hymenium 190–210 (–240) µm tall, inspersed with oil droplets; oval-ellipsoidal ascospores, 15–21(–24) × (8·5–)9–12 µm; and curved, thread-like, conidia, 21–24 ×1 µm.
Placopsis subcribellans is known from southern South America in heavily glaciated, high-rainfall areas of southern Chile from lat. 44°S to 55°S (Lamb Reference Lamb1947; Galloway Reference Galloway2002) and from southern New Zealand (Galloway Reference Galloway2007; D. J. Galloway, unpublished).
New records. Chile: XII Región: Isla Desolación, 52°51′S, 74°28′W, Hebe scrub along S shore of Caleta San José, Bahía Tuesday, 1969, H. A. Imshaug 44738 & K. Ohlsson (MSC).—Argentina: Tierra del Fuego: Isla Grande, Bahía Buen Suceso, 54°47′S, 65°16′W, open landslide area on slope, inland from N side of head of bay, 1971, H. A. Imshaug 50230 & K. Ohlsson (MSC). Isla de los Estados: Puerto Hoppner, 54°47′S, 64°25′W, littoral zone at head of inner bay, s. lat., 1971, H. A. Imshaug 53784 & K. Ohlsson (MSC); Puerto Alexander, 54°50′S, 64°25′W, densely shaded scrub at base of mountain at head of cove, 1971, H. A. Imshaug 52863 & K. Ohlsson (MSC).
Revised key to species of Placopsis and Aspiciliopsis in southern South America
1 Thallus with soredia or isidia ... 2
Thallus without isidia or soredia ... 10
2(1) Sorediate ... 3
Isidiate ... 7
3(2) Thallus rosette-forming, not of small squamules; soralia eroding, often with a well-defined margin ... 4
Thallus of small squamules ... 6
4(3) Soralia with pale greenish, whitish or greyish soredia ... 5
Soralia with dark green to blackish soredia ... P. lambii
5(4) Thallus olive greenish to brownish with a pale-lilac tinge, uniformly velvety pruinose (×10 lens); hymenium 115–140(–160) µm tall ... P. fusciduloides
Thallus pale greenish white to fawnish ivory, with occasional, scattered patches of pruina or epruinose; hymenium 160–210 µm tall ... P. gelida
6(3) Marginal squamules with spots of white pruina (×10 lens); soralia excavate to spreading ... P. microphylla
Marginal squamules without spots of white pruina; soralia capitate ... ... P. rhodocarpa
7(2) Isidia small, fragile, easily dislodged and leaving pits (×10 lens) ... 8
Isidia large, globose to finger-like, not leaving pits ... 9
8(7) Thallus small [1–3(–5) cm diam.]; lobes separating at apices; upper surface not glossy ... P. cribellans
Thallus larger [2–5(–8) cm diam.]; lobes contiguous, separated by long, narrow cracks; upper surface glossy (like polished ivory) ... P. subcribellans
9(7) Marginal prothallus present; isidia globose; ascospores 10–15 × 5–8 µm; stictic acid present ... P. tuberculifera
Marginal prothallus absent; isidia subglobose to finger-like; ascospores (15–)18–24 × (6–)7–9(–10) µm; stictic acid absent ... P. pycnotheca
10(1) Thallus of small squamules, 0·1–0·5 mm diam. ... 11
Thallus crustose or crustose-lobate, continuous, not squamulose ... 12
11(10) Thallus effuse, indeterminate; squamules minute, 0·05–0·2 mm diam. ... P. effusa
Thallus determinate; squamules thicker 0·1–0·5 mm diam. ... P. parellina
12(10) Thallus rust-coloured, orange to reddish ... 13
Thallus not rust-coloured ... 15
13(12) Conidia filiform, curved, 18–35 µm long ... 14
Conidia rod-shaped, 5·4–7·5(–10) µm long ... P. baculigera
14(13) Thallus lobes with a pale, grey-brown marginal zone; hymenium 200–300 µm tall; ascospores 25–30 × 15–18 µm ... P. imshaugii
Thallus lobes without a pale grey-brown marginal zone; hymenium 160–240 µm tall; ascospores 18–24 × 10–15 µm ... P. bicolor
15(12) Apothecia sessile at maturity ... 16
Apothecia immersed (aspicilioid) at maturity ... Aspiciliopsis macrophthalma
16(15) Upper surface pruinose ... 17
Upper surface not pruinose ... 18
17(16) Thallus thick, tartareous; glistening white-pruinose in patches towards margins; marginal lobes swollen ... P. roivainenii
Thallus not tartareous; ±uniformly grey-white pruinose; marginal lobes flattened ... ... P. fuscidula
18(16) Upper surface deeply areolate-cracked or verrucose-papillate, especially centrally ... 19
Upper surface plane, not areolate-cracked or verrucose-papillate ... 22
19(18) Upper surface verrucose-papillate or wrinkled-knobbly centrally ... 20
Upper surface areolate-cracked centrally, not verrucose-papillate ... 21
20(19) Thallus brown-grey, olive-brown or brown-black; marginal lobes discrete, flattened; apices furcate or divergent, surface glossy ... P. perrugosa
Thallus grey-white to rusty brownish; marginal lobes contiguous or overlapping, swollen; apices not furcate or divergent, surface matt ... P. contortuplicata
21(19) Surface of areolae minutely cerebriform (×10 lens); areolae separated by deep cracks and appearing as distinctive ‘islands’; lobes flat not convex-bullate ... P. dusenii
Surface of areolae not minutely cerebriform; lobes convex-bullate, in distinctive, parallel lines ... P. gelidioides
22(18) Thallus crustose, thin, forming mosaics and delimited by a narrow line of prothallus; surface delicately white-maculate (×10 lens); cephalodia immersed ... ... P. tararuana
Thallus lobate, rosette-forming, without a marginal prothallus; surface glossy, like polished ivory, without maculae; cephalodia sessile ... P. stenophylla
I am grateful to Dr Alan Fryday (MSC) for access to specimens collected by Henry Imshaug and Karl Ohlsson; to Prof. H. A. Imshaug (Okemos, Michigan) for providing information on his South American collecting sites and their numbers; to Prof. Lars Arvidsson (Göteborg), Prof. Wanda Quilhot (Valparaíso), Prof. Arve Elvebakk (Tromsø), Prof. Ulrik Søchting (Copenhagen), Dr Imke Schmitt (Chicago) and the Australian National Botanic Gardens Herbarium (CANB), for provision of specimens; and to Prof. Jack Elix (Canberra) for chemical analyses.
