Telopea Volume 18: 19-26 Publication date: 20 January 2015 The Royal Journal of Plant Systematics Botanic Gardens dx.doi.org/10.7751/telopea8144 & Domain Trust plantnet.rbgsyd.nsw.gov.au/Telopea • escholarship.usyd.edu.au/journals/index.php/TEL • ISSN 0312-9764 (Print) • ISSN 2200-4025 (Online) The Lichen Genus Pertusaria in Rarotonga, Cook Islands Alan W. Archer and John A. Elix 1 2 1National Herbarium of New South Wales, Royal Botanic Gardens and Domain Trust, Mrs Macquaries Road, Sydney, NSW 2000, Australia 2Research School of Chemistry, Building 137, Australian National University, Canberra, ACT 2601, Australia Abstract The first account of the lichen genus Pertusaria (Pertusariaceae) on the island of Rarotonga (Cook Islands) is given. A total of 8 taxa are recorded, of which 5 are new to science viz: Pertusaria atroguttata, P. homilocarpa, P. megacarpa, P. rarotongensis and P. rarotongensis var. stictica. A key to the species is provided. Introduction The Cook Islands are located between Tonga and the islands of French Polynesia in the South Pacific Ocean and consist of a group of 15 islands formed into a widely scattered northern group and a more compact southern group with a total land area of 237 square kilometres. The island of Rarotonga is in the southern group, at 21°12,-21°15,S, 159°44'-159°50'W, and with an area of 67.4 square kilometres is the largest of the islands. An introduction to the geology, landforms, vegetation and lichenological history of the island has been provided by McCarthy (2000). The climate is warm, humid tropical with an average humidity of 80-85%, an average annual rainfall of 2200 mm and with a winter temperature range of 20-26°C, rising to 24-30°C in the summer months. This paper forms the fourth recent contribution on the lichens of Rarotonga following accounts of the pyrenocarpous lichens (McCarthy 2000), the Parmeliaceae (Louwhoff and Elix 2000) and Ramalina (Blanchon and de Lange 2011). The lichen genus Pertusaria has not previously been reported from the Cook Islands (Elix and McCarthy 1998). Materials and methods Specimens were collected on the island of Rarotonga in June 1998 and later examined using Olympus VMT and Olympus BHA microscopes. The chemistry of the species was studied by thin layer chromatography (Elix 2014) and comparison with authentic samples. Photographs of the specimens were taken with a Cannon EOS camera fitted with a Cannon MP 65mm f 2.8, l-5x lens, at a magnification of x4. © 2015 Royal Botanic Gardens and Domain Trust 20 Telopea 18: 19-26, 2015 Archer and Elix New species Pertusaria atroguttata A.W.Archer & Elix, sp. nov. Fig. 1 MB 810572 Diagnosis: Similar to Pertusaria alboatra Zahlbr. but differs in lacking thiophaninic acid and in having three ascospores per ascus. Type: Cook Islands, Rarotonga: mouth of Avana Stream, 21°14'S, 159°43'W, alt. 1 m, on Hibiscus in strand vegetation, J.A.Elix 42992, 9 Jun 1998; holotype: CANB. Thallus off-white, epiphloedal, surface tuberculate, slightly cracked, subnitid, soredia and isidia absent; apothecia verruciform, conspicuous, concolorous with the thallus, hemispherical, sunken above, constricted at the base, 0.8-1.5 mm diam. ostioles black, conspicuous, 0.2-0.25 mm diam., 2-4 per verruca; ascospores 3 per ascus, ellipsoid, inner spore wall smooth, 90-120 pm long, 32-40 pm wide. Chemistry: 2'-0-methylperlatolic acid (major), 2'-0-methylstenosporic acid (minor), planaic acid (minor), methyl 2'-0-methylperlatolate (minor) and methyl planaiate (minor). Etymology: from the Latin atro, black and guttatus, spotted from gutta, a drop, or spot, a reference to the conspicuous black ostioles. Substrate and ecology: It grows on the bark of Hibiscus in strand vegetation. Discussion: Pertusaria atroguttata is characterised by the conspicuous black ostioles on white apothecia and the presence of 2'-0-methylperlatolic acid as a major lichen compound. This compound distinguishes the new species from the somewhat similar P. alboatra Zahlbr. (Zahlbruckner 1941) which only contains thiophaninic acid. Pertusaria atroguttata also resembles P. melaleucoid.es Mull. Arg. (Muller 1884) from New Zealand, as this species also has conspicuous black ostioles [cf. Fig. 1 in Archer 1991, as P. atropunctata] but lacks lichen compounds. The recently described Pertusaria parasommerfeltii Q.Ren from China (Ren 2014) also resembles P. atroguttata [cf. Fig. 2 in Ren 2014] but that species has eight ascospores per ascus and contains 4,5-dichlorolichexanthone in addition to 2'-0-methylperlatolic acid. At present this new species is only known from the type specimen. Fig-1 . Pertusaria atroguttata, holotype. Scale: 1 mm Pertusaria in Rarotonga Telopea 18: 19-26, 2015 21 Pertusaria homilocarpa A.W.Archer & Elix, sp. nov. Fig. 2 MB 810573 Diagnosis: Similar to Pertusaria pertusella Mull. Arg. but with apothecial verrucae which are constricted at the base, and with smaller ascospores and darker ostioles. Type: Cook Islands, Rarotonga: mouth of Avana Stream, 21°14'S, 159°43'W, alt. 1 m, on Hibiscus in strand vegetation, J.A.Elix 43007, 9 Jun 1998; holotype: CANB. Thallus pale greenish white, epiphloedal, surface smooth to subtuberculate, subnitid, slightly cracked, soredia and isidia absent; apothecia verruciform, concolourous with the thallus, numerous, crowded, sometimes confluent, flattened hemispherical, constricted at the base, 0.7-0.9 mm diam., confluent verrucae to 1.2 mm diam.; ostioles black, punctiform, 1-4 per verruca; ascsospores 2 per ascus, fusiform-ellipsoid, inner spore wall smooth, 90-110 pm long, 28-32 pm wide. Chemistry: 2,5-dichlorolichexanthone (minor), 2,4-dichlorolichexanthone (trace), 2,4,5-trichlorolichexanthone (minor), stictic acid (major), constictic acid (minor) and cryptostictic acid (trace). Etymology: From the Greek, homilos, a crowd or throng, and carpus, fruit, a reference to the crowded apothecia. Substrate and ecology: It grows on the bark of Hibiscus in strand vegetation. Discussion: Pertusaria homilocarpa is characterised by asci with two ascospores and the presence of 2,5-dichlorolichexanthone, 2,4-dichlorolichexanthone, 2,4,5-trichloro-lichexanthone and stictic acid. This combination of characters is also present in P. pertusella Mull. Arg. (Muller 1884; Archer 1997) and P. nigrescens Srivastava & Awasthi (Awasthi & Srivastava 1993), but in these two species the apothecial verrucae are not constricted at the base as is P. homilocarpa. The ostioles in P. homilocarpa are black and punctiform in contrast to the ostioles present in P. pertusella which are pale to dark brown and these two species are further differentiated by the size of the ascospores, 90-110 pm long in P. homilocarpa and 100-140(-160) pm long in P. pertusella. At present this new species is only known from the type specimen. Fig 2 . Pertusaria homilocarpa, holotype. Scale: 1 mm 22 Telopea 18: 19-26, 2015 Archer and Elix Pertusaria megacarpa A.W.Archer & Elix, sp. nov. Fig. 3 MB 810574 Diagnosis: similar to Pertusaria parnassia Vain, but lacking lichexanthone and stictic acid. Type: Cook Islands, Rarotonga: mouth of Avana Stream, 21°14'S, 159°43'W, alt. 1 m, on Hibiscus in strand vegetation, J.A.Elix 42998, 9 Jun 1998; holotype: CANB. Thallus pale olive green,surface subtuberculate, subnitid, rarely cracked, margin entire and not zoned; soralia and isidia absent. Apothecia verruciform, conspicuous, scattered or sometimes confluent, flattened hemispherical, concolourous with the thallus, 1-1.8 mm diam. Ostioles conspicuous, pale, translucent, one per verruca, sunken, 0.2-0.3 mm diam. Ascospores 8 per ascus, 2-seriate, initially ellipsoid, becoming fusiform- ellipsoid, inner spore wall rough, 120-150 pm long, 34-42 pm wide. Chemistry: no lichen substances detected. Etymology: from the Greek mega, large and carpus, fruit, a reference to the large apothecia. Substrate and ecology: It grows on the bark of Hibiscus in strand vegetation. Comments: The new species is characterised by the large apothecia, the eight rough-walled ascospores per ascus and the absence of lichen compounds. This latter feature distinguishes the new species from P. parnassia Vain., described from Guadoloupe (Vainio 1899), as this contains lichexanthone and stictic acid and has eight ascospores with rough inner walls. In addition the ostioles in P. parnassia are black and punctiform, quite distinct from the large translucent ostioles present in P. megacarpa. Pertusaria species with eight rough-walled ascospores are rare and only two other such species are known viz: P. anomalospora A.W.Archer, Elix & Streimann (Archer et. al. 1995), described from Papua New Guinea and which contains isomeric dichlorolichexanthones and has ascospores 105-135 pm long, and P. lambinonii A.W. Archer, Elix, Eb. Fisch. Killmann & Serus. (Archer et al. 2009), described from Central Africa, which contains lichexanthone, planaic acid, 2’-0-methylperlatolic acid and protocetraric acid, and has ascospores 80-125 pm long. Additional specimen examined: Cook Islands, Rarotonga: mouth of Avana Stream, 21°14'S, 159°43'W, alt. 1 m, on Hibiscus in strand vegetation, J-A.Elix 42985, 9 lun 1998; (CANB). Fig. 3 . Pertusaria megacarpa, holotype. Scale: 1 mm Pertusaria in Rarotonga Telopea 18: 19-26, 2015 23 Pertusaria rarotongensis A.W.Archer & Elix, sp. nov. Fig. 4 MB 810575 Diagnosis: similar to Pertusaria bogia A.W.Archer & Elix but differs in lacking stictic acid and in having ascospores with a rough inner wall. Type: Cook Islands, Rarotonga: mouth of Avana Stream, 21°14'S, 159°43'W, alt. 1 m, on Hibiscus in strand vegetation, J.A.Elix 42986, 9 Jun 1998; holotype: CANB. Thallus pale olive green, epiphloedal, margin entire and not zoned; surface subtuberculate, slightly cracked, subnitid, soredia and isidia absent; apothecia verruciform, concolourous with the thallus, hemispherical 0.4-0.5 mm diam., the majority becoming confluent to form irregular, flattened apothecia, approximately 2-3.5 mm long and 1-2 mm wide; ostioles black, punctiform, 1 per verruca but up to 18 in confluent verrucae. Ascospores 3 (or 4) per ascus, ellipsoid, the inner spore wall slightly roughened, 74-100 pm long and 34-40 pm wide. Chemistry: 4,5-dichlorolichexanthone (minor), 2'-0-methylconfluentic acid (major) and confluentic acid (trace). Etymology: from Rarotonga and ensis, place of origin. Substrate and ecology: It grows on the bark of Hibiscus in strand vegetation. Comments: Pertusaria rarotongensis is characterised by the multi-ostiolate, flattened apothecia and the presence of 2-O-methylconfluentic acid and is similar to P. bogia A.W.Archer & Elix described from Papua New Guinea (Archer & Elix 1998). However, the new species is differentiated from P. bogia by the absence of stictic acid (present in P. bogia) and the rough walled ascospores (smooth walled in P. bogia). Table 1. Comparisons of Pertusaria bogia, P. rarotongensis var. rarotongensis and P. rarotongensis var. stictica. Legend: - = absent; + = present Taxon spore length (pm) inner spore wall stictic acid P. bogia 85-125 smooth R rarotongensis var. rarotongensis 74-100 rough P. rarotongensis var. stictica 105-130 rough + Fig. 4. Pertusaria rarotongensis, holotype. Scale: 1 mm 24 Telopea 18: 19-26, 2015 Archer and Elix 2'-0-Methylconfluentic acid is an uncommon lichen compound in Pertusaria and is presently known from only five taxa. Two species containing 2'-0-methylconfluentic acid are known from North America, the corticolous, two-spored P. saximontana Wetmore and the saxicolous, four-spored P. arizonica Dibben (Dibben 1980). In addition there is the isidiate, sterile P. georgeana var. occidentalis Elix & A.W.Archer from Western Australia (Archer & Elix 2009) and P. bogia A.W.Archer & Elix, from Papua New Guinea but these two species are morphologically distinct from P. rarotongensis. A similar taxon, but with additional stictic acid is described as Pertusaria rarotongensis var. stictica below; the differences between P. bogia, P. rarotongensis var. rarotongensis and P. rarotongensis var. stictica are shown in Table 1. At present this new species is only known from the type specimen. Pertusaria rarotongensis var. stictica A.W.Archer & Elix, var. nov. Fig. 5 MB 810576 Diagnosis: similar to Pertusaria rarotongensis (vide supra) but containing additional stictic acid. Type: Cook Islands, Rarotonga, Taputarangi Track, 21°12'S, 159°48'W, alt. 100 m, on fallen tree in relatively open tropical forest, J.A.Elix 42748, 6 Junl998; holotype: CANB. Thallus pale olive green, epiphloedal, margin entire and not zoned; surface smooth, slightly cracked, subnitid, soredia and isidia absent; apothecia verruciform, concolourous with the thallus, hemispherical, constricted at the base, often confluent; individual apothecia 0.6-1.0 mm diam. but confluent apothecia flattened, 2.5-4 mm long and 1-2 mm wide; ostioles black, punctiform surrounded by a pale grey, translucent zone, 1 or 2 in individual verruca but 7-18 in confluent verrucae. Ascospores narrow ellipsoid, inner spore wall rough, 3(or 4) per ascus, 105-130 mm long, 30-43 mm wide. Chemistry: 4,5-dichlorolichexanthone (minor), stictic acid (major), constictic acid (minor), cryptostictic acid (trace) and 2'-0-methylconfluentic acid (major) Etymology: Like P. rarotongensis but containing additional stictic acid. Substrate and ecology: on the bark of a fallen tree in relatively open tropical forest. Comments: The new variety resembles P. rarotongensis but contains additional stictic acid. At present this new species is only known from the type specimen. Fig. 5 Pertusaria rarotongensis var. stictica. Scale: 1 mm Pertusaria in Rarotonga Telopea 18: 19-26, 2015 25 New Reports Pertusaria commutata Miill.Arg. Flora 67: 269 (1884) Pertusaria commutata Miill.Arg. is characterised by disciform apothecia with one ascospore per ascus and the presence of haemathamnolic acid. Specimen examined: Cook Islands, Rarotonga: Te Kou Track, lower level, 21°13'S, 159°46'W, alt. 80 m, on Cecropia branch in scattered regrowth forest and taro gardens, J.A.Elix 42853, 7 lun 1998 (CANB). Pertusaria montpittensis A.W.Archer in J.A.Elix, H.Streimann & A.W.Archer, Proceedings of the Linnean Society of New South Wales 113: 65 (1992) Pertusaria montpittensis A.W.Archer is characterised by an isidiate thallus lacking apothecia and containing 4,5-dichlorolichexanthone and stictic acid. It grows on both corticolous and saxicolous substrata. Specimens examined: Cook Islands, Rarotonga: Avana Stream, 400 m E of water tanks, 21°14'S, 159°45'W, alt. 60 m, on Hibiscus in moist, lowland tropical forest, J.A. Elix 42802, 6 Jun 1998 (CANB); Te Kou Track, lower level, 21°13'S, 159°46'W, alt. 80 m, on basalt/breccia rocks in scattered regrowth forest and taro gardens with rock outcrops, J.A. Elix 42828, 7 Jun 1998 (CANB); J.A.Elix 42829 (CANB); Raemaru Track, upper level, 21°14'S, 159°49'W, alt. 200 m, on treelet in fern dominated slopes with scattered Albizzia, J.A. Elix 42904, 8 Jun 1998 (CANB); mouth of Avana Stream, 21°14'S, 159°43'W, alt. 1 m, on Hibiscus in strand vegetation, J.A.Elix 42999, 9 Jun 1998 (CANB) Pertusaria thiospoda C.Knight Transactions of the Linnean Society of London, Botany 2: 47 (1882) Pertusaria thiospoda C.Knight is characterised by verruciform apothecia with two ascospores per ascus and the presence of thiophaninic and stictic acids. Specimen examined: Cook Islands, Rarotonga: mouth of Avana Stream, 21°14'S, 159°43'W, alt. 1 m, on Hibiscus in strand vegetation, J.A.Elix 43002,9 Jun 1998 (CANB). Varicellaria velata (Turner) Schmitt & Lumbsch Mycokeys 4: 31 (2012) Pertusaria velata (Turner) Nyl. Lich. Scand. (Uppsala): 179 (1861) Parmelia velata Turner Transactions of the Linnean Society of London 9: 143 (1808) Varicellaria velata is characterised by disciform apothecia with one ascospore per ascus and the presence of lecanoric acid. The species was recently transferred from Pertusaria to Varicellaria (Schmitt et al. 2012) and is therefore not included in the Key below. Specimens examined: Cook Islands, Rarotonga: Avana Stream, 400 m E of water tanks, 21°14’S, 159°45’W, alt. 60 m, on Hibiscus in moist, lowland tropical forest, J.A. Elix 42794,6 Jun 1998 (CANB); mouth of Avana Stream, 21°14’S, 159°43'W, alt. 1 m, on Hibiscus in strand vegetation, J.A. Elix 42993, 9 Jun 1998 (CANB). Key to the genus Pertusaria in Rarotonga 1 Apothecia lacking, with isidia.P. montpittensis 1: Apothecia verruciform or disciform . 2 2 Thallus with disciform apothecia; thallus K+yellow, C-ve; haemathamnolic acid present.... P. commutata 2: Thallus with verruciform apothecia. 3 3 Ascospores with rough inner wall .4 3: Ascospores with smooth inner wall.6 4 Ascospores 8 per ascus, 120-150 pm long; lichen compounds absent. P. megacarapa 4: Ascospores 3 or 4 per ascus, 74-130 pm long; 2’-0-methylconfluentic acid present.5 5 Stictic acid present.P. rarotongensis var. stictica 5: Stictic acid absent.P. rarotongensis var. rarotongensis 6 Ascospores 2 per ascus; ostioles not black and conspicuous. 7 6: Ascospores 3-4 per ascus; ostioles black, conspicuous .P. atroguttata 7 Ostioles pale yellow; thiophaninic acid present. P. thiospoda 7: Ostioles black, punctiform; thiophaninic acid absent.P. homilocarpa 26 Telopea 18: 19-26, 2015 Archer and Elix Conclusion The genus Pertusaria exhibits a high degree of endemism throughout its distribution. Approximately 45% of Australian taxa are endemic (Archer 2004), 50% of New Zealand (Galloway 2007) and total North American species (Dibben 1980), while in temperate North America approximately 75% are endemic to the continent. Given this background, the fact that 5 of the 8 taxa recorded for Rarotonga are endemic is not as surprising as it initially appears. Acknowledgments We thank Gerald McCormack from the Cook Island National Heritage Project for his support and advice, Patrick McCarthy and Simone Louwhoff for accompanying JAE in the field and the Australian Research Council for generous financial assistance. References Archer AW (1991) New species and new reports of Pertusaria (lichenised Ascomycotina) from Australia and New Zealand with a key to the species in Australia. My cotaxon 41: 223-269. Archer AW (1997) The lichen genus Pertusaria in Australia. Bibliotheca Lichenolologica 69: 5-249. Archer AW, Elix JA, Streimann H (1995) The lichen genus Pertusaria (lichenised Ascomycotina) in Papua New Guinea. My cotaxon 56: 387-401. Archer AW, Elix JA (1998) Additional new species and two new reports in the lichen genus Pertusaria (Lichenised Ascomycotina) from Papua New Guinea. Mycotaxon 67: 155-179. Archer AW, Elix JA (2009) New taxa and new reports of Australian Pertusaria (lichenised Ascomycota), Pertusariaceae. 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Denkschriften der Akademie der Wissenschaften in Wien mathematisch-naturwissenschaftliche Klasse 104: 249-380. Manuscript received 20 October 2014, accepted 10 December 2014