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THE LICHENS OF RAROTONGA, COOK ISLANDS, SOUTH PACIFIC OCEAN II: PARMELIACEAE
Lichenologist 32(1): 49–55 (2000) Article No. lich.1999.0237 Available online at http://www.idealibrary.com on
THE LICHENS OF RAROTONGA, COOK ISLANDS, SOUTH PACIFIC OCEAN II: PARMELIACEAE Simone H. J. J. LOUWHOFF* and John A. ELIX*
Abstract: Ten parmelioid taxa in five genera were identified from Rarotonga, Cook Islands, South Pacific Ocean. These comprise: three species of Bulbothrix, one species of Canoparmelia, four species of Parmotrema, one species of Rimelia and one species of Xanthoparmelia. Canoparmelia rarotongensis Louwhoff & Elix is described as new, being distinguished from other species of this genus by its unique secondary chemistry (lecanoric acid) and conspicuous, inflated isidia. The majority of parmelioid lichens on Rarotonga have cosmopolitan and pantropical distributions. Bulbothrix is reported for the first time from the Polynesian region. 2000 The British Lichen Society
Introduction Rarotonga is the largest and the highest (653 m) of the Cook Islands, and is situated between latitudes 2112 –15 S and longitudes 15944 –50 W, in the South Pacific Ocean. The island is estimated to be 2 million years old and was formed during a series of volcanic eruptions (McCormack & Künzle 1991). Mueller-Dombois & Fosberg (1998) and Merlin (1985) provided a detailed discussion on the vegetation of the Cook Islands. An introduction to the geology, landforms, vegetation and lichenological history of the island has been provided by McCarthy (2000). The lichen family Parmeliaceae is well-represented in the Southern Hemisphere, but our knowledge of the distribution of parmelioid lichens across the Pacific is limited (Elix & McCarthy 1998). About 150 parmelioid taxa in 25 genera are currently reported for the smaller Pacific Islands (Elix & McCarthy 1998; Louwhoff & Elix 1998). This paper includes a key to the Parmeliaceae of Rarotonga, brief comments on the species, and a description of the new species Canoparmelia rarotongensis. As such, it is the first comprehensive treatment of the family Parmeliaceae in the region, as only Parmotrema cristiferum was reported from Rarotonga previously. Materials and Methods More than 150 specimens of Parmeliaceae were collected from a variety of habitats on Rarotonga and were subsequently examined using morphological and chemical characteristics. Chemical constituents were identified by thin layer chromatography (Culberson, 1972; Culberson et al. 1981; Culberson & Johnson 1982; Elix & Ernst-Russell 1993; Elix et al. 1988), and high performance liquid chromatography (Feige et al. 1993). *Chemistry Department, The Faculties, Australian National University, Canberra 0200, A.C.T., Australia. 0024–2829/00/010049+07 r35.00/0
2000 The British Lichen Society
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Results Ten species in five genera were recognized among Rarotongan collections of Parmeliaceae. Parmotrema cristiferum, P. tinctorum and Rimelia reticulata are common lichens in many regions of the world and are also widespread across the Pacific (Elix & McCarthy 1998). Parmotrema endosulphureum, Bulbothrix isidiza, B. goebelii and B. tabacina are pantropical species, and their distribution in the Pacific region is limited (Elix & McCarthy 1998). The genus Bulbothrix has not been encountered previously in the Polynesian region.
Key to the Parmeliaceae of Rarotonga 1
Lower surface erhizinate at lobe margins . . . . . . . . . . . . . 2 Lower surface rhizinate to lobe margins . . . . . . . . . . . . . . 6
2(1)
Lobes narrow (2–4 mm wide); lower surface with a narrow (up to 10 mm wide), erhizinate marginal zone . . . . . . . . . . . . . . . . . . Canoparmelia rarotongensis Lobes broad (5–20 mm wide); lower surface with a broad (up to 10 mm wide) erhizinate marginal zone . . . . . . . . . . . . . 3
3(2)
Thallus sorediate; medulla K+yellow then red; salazinic acid present . . . . . . . . . . . . . . . . . . . . . Parmotrema cristiferum Thallus isidiate; medulla K; salazinic acid absent . . . . . . . 4
4(3)
Medulla pale orange-yellow; C+pink; gyrophoric acid present . . . . . . . . . . . . . . . . . Parmotrema endosulphureum Medulla white, Cor C+red; gyrophoric acid absent . . . . . . 5
5(4)
Medulla . . . Medulla . . .
6(1)
Upper cortex effigurately maculate to reticulately cracked; thallus sorediate . . . . . . . . . . . . . . . . . . . Rimelia reticulata Upper cortex emaculate or faintly maculate; thallus isidiate . . . 7
7(6)
Cortex K; usnic acid present; lobe margins eciliate . . . . . . . . . . . . . . . . . . Xanthoparmelia subramigera Cortex K+yellow; usnic acid absent; lobe margins with bulbate cilia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
8(7)
Medulla K, C+pink; gyrophoric acid present . . . . . . . . . . . . . . . . . . . . . . . . Bulbothrix goebellii Medulla K+yellow then red; salazinic acid present . . . . . . . . 9
9(8)
Lower cortex black . . . . . . . . . . . . . . Bulbothrix tabacina Lower cortex pale . . . . . . . . . . . . . . . . Bulbothrix isidiza
C+red; lecanoric acid present; lobesflat . . . . . . . . . . . . . . . . . . Parmotrema tinctorum C; protocetraric acid present; lobesfolded . . . . . . . . . . . . . . . . Parmotrema saccatilobum
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The Species 1. Bulbothrix goebelii (Zenker) Hale This species is finer than either of the other two taxa in this genus described from Rarotonga, with narrow (0·5–1·5 mm wide) lobes, a black lower cortex, atranorin and chloroatranorin in the cortex, and gyrophoric acid (major) and lecanoric acid (trace) in the medulla. Apothecia and pycnidia not seen but the former have been reported previously (Elix 1994). Specimens collected appeared to belong to one of two categories, fine-lobed or broader-lobed. These are not recognized as different taxa and are simply referred to as different morphotypes of B. goebelii. All three Bulbothrix species recognized from Rarotonga are isidiate and pantropical in distribution. Representative specimens examined (total 14): Cook Islands: Rarotonga: Muri Lagoon, near mouth of Avana stream, 2115 S, 15944 W, 1 m, on trees above beach, 1998, J. A. Elix 42712 (CANB); Raemaru Track, 2114 S, 15949 W, 100–200 m, in fernland encroaching upon Albizzia/Allocasuarina forest, on Albizzia, 1998, S. Louwhoff 571 (CANB).
2. Bulbothrix isidiza (Nyl.) Hale Only one specimen of this species was collected on Rarotonga. This species has atranorin and chloroatranorin in the cortex, salazinic acid (major) and consalazinic acid (minor) in the medulla, and a pale lower cortex. Apothecia and pycnidia not seen but reported previously (Elix 1994). In the Pacific it was previously reported for the Hawaiian Islands (Elix & McCarthy 1998). Specimen examined. Cook Islands: Rarotonga: Te Rua Manga Track, climb to the base of Te Rua Manga (The Needle), 2114 S, 15946 W, c. 250 m, corticolous in slope forest with native tree species Pittosporum and Weinmannia, 1998, S. Louwhoff 615 (CANB).
3. Bulbothrix tabacina (Mont. & Bosch) Hale This species is characterized by the presence of atranorin and chloroatranorin in the cortex, salazinic acid (major) and consalazinic acid (minor) in the medulla, and by the black lower cortex. The latter sets it apart from B. isidiza (see above). Some specimens collected on Rarotonga were broader than usual (10 mm cf. 1·5–5 mm wide) and occasionally displayed marginal lobules. Apothecia not seen but reported previously (Elix 1994). Pycnidia, not previously reported (Elix 1994), were observed to be sparse on three specimens; conidia rod-shaped to elongate-unciform, (4·5–)5–7·5(–8)1 m. Representative specimen examined (total 29): Cook Islands: Rarotonga: Raemaru Track, steep slope to summit cliff, 2113 S, 15948 W, 200 m, on Paraserianthes falcataria in disturbed forest, 1998, S. Louwhoff 563 (CANB).
4. Canoparmelia rarotongensis Louwhoff & Elix, sp. nov. Species cum thallo ut in Canoparmelia owariensis sed ab hac specie thallo corticolo, laxe adnato, isidiis apicibus non erumpentibus et acido lecanorico continente differt. Typus: Cook Islands, Rarotonga, Muri Lagoon, 2115 S, 15944 W, 1 m, on Hibiscus along the foreshore, 6 June 1998, J. A. Elix 42730 (Holotypus—CANB).
(Fig. 1)
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F. 1. Holotype of Canoparmelia rarotongensis (J. A. Elix 42730 in CANB). Scale in millimetres.
Thallus moderately adnate, membranaceous, up to 6 cm wide. Lobes irregular,contiguous and contorted centrally,constricted at base of apices, where lobes become separated, 2–4 mm wide; margins entire, occasionally becoming subcrenate, mainly flat, eciliate. Upper surface pale, dusty grey-green, emaculate, irregularly cracked centrally, isidiate; isidia consistently conspicuously inflated, mostly branched, each isidiate cluster up to 0·5 mm wide and up to 0·8(–1) mm high, predominantly laminal. Medulla white. Lower surface black, dull, with a pale brown, narrow (up to 1 mm wide) erhizinate marginal zone; rhizines black, sparse to moderately dense, coarse, simple. Apothecia and pycnidia not seen. Chemistry. Cortex K+yellow; medulla K, C+red, PD; containing atranorin, chloroatranorin, lecanoric acid (major), orsellinic acid (trace), orcinol (trace). Canoparmelia rarotongensis is known only from the type collection, where it occurred on Hibiscus in a coastal site. Notes. The new species is characterized by the conspicuous isidia, which are consistently inflated, branched, but which do not become sorediate, and by the presence of atranorin and chloroatranorin in the cortex, and lecanoric acid in the medulla. The new species can be readily distinguished from other species of Canoparmelia by the above characteristics (Elix 1994; Elix et al.
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1986). Lecanoric acid has not previously been detected in this genus. Only three species of Canoparmelia, C. caroliniana, C. scrobicularis and C. texana, have been reported for the Pacific region (Elix & McCarthy 1998). The new species is morphologically and chemically distinct from these, and has been named for its type locality. 5. Parmotrema cristiferum (Taylor) Hale This species has a cosmopolitan distribution (but is absent from Europe) and is known to be widespread in the Pacific region. Apothecia and pycnidia not seen but the former have been reported previously (Elix 1994). It is a morphologically variable species characterized by sorediate lobes, and by the presence of atranorin, chloroatranorin, salazinic acid (major), consalazinic acid (minor) and eumitrin A1 (trace). Representative specimen examined (total 19): Cook Islands: Rarotonga: Taputarangi Track, in slope forest, 2112 S, 15948 W, 160 m, on twig, 1998, J. A. Elix 42771 (CANB).
6. Parmotrema endosulphureum (Hillm.) Hale Although Parmotrema endosulphureum has been reported for North, Central and South America, and for East Africa (Hale 1965), in the Pacific region it has only been recorded from Fiji (Hale 1965), the Cocos Islands (Costa Rica) and the Galapagos Islands (Elix & McCarthy 1998). Parmotrema endosulphureum is isidiate, has atranorin and chloroatranorin in the cortex, and gyrophoric acid and the eumitrin N complex in the medulla, the latter being responsible for the pale orange-yellow colouration of the medulla. Apothecia and pycnidia not seen but the former have been reported previously (Hale 1965). Representative specimen examined (total 2). Cook Islands: Rarotonga: Te Ko’u Track, near taro plantations, 2113 S, 15946 W, 100 m, on rock, 1998, J. A. Elix 42822 (CANB).
7. Parmotrema saccatilobum (Taylor) Hale This species primarily has a South-East Asian distribution, but is also widespread across the Pacific, with the type collected from Pitcairn Island. It is characterized by a large, loosely attached thallus, folded lobes, isidia, and by the presence of atranorin, chloroatranorin and protocetraric acid. This species was morphologically quite variable on Rarotonga. One specimen was observed to produce pycnidia, not previously reported for this species (Elix 1994); the conidia were found to be elongated filiform, 7–121 m. One specimen was fertile, although the spores were slightly longer than usually reported [30 cf. 22–26 m (Hale 1965)]. Representative specimen examined (total 13). Cook Islands: Rarotonga: Te Ko’u Track, taro plantations in Takuva’ine Valley, 2113 S, 15946 W, 60–100 m, on boulders in disturbed habitat, 1998, S. Louwhoff 529 (CANB).
8. Parmotrema tinctorum (Despr. ex Nyl.) Hale This is a cosmopolitan species that is also widespread across the Pacific. Parmotrema tinctorum is morphologically variable, but can be recognized by the
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large thallus, isidiate, broad lobes (up to 2–2·5 cm wide), and by the presence of atranorin, chloroatranorin and lecanoric acid (traces of orsellinic acid and orcinol). Apothecia and pycnidia not seen but reported previously (Elix 1994). Representative specimen examined (total 40). Cook Islands: Rarotonga: at the mouth of Avana stream, 2114 S, 15943 W, 1 m, on seashore trees (Hibiscus and palm), 1998, J. A. Elix 42991 (CANB).
9. Rimelia reticulata (Taylor) Hale & A. Fletcher A very common, cosmopolitan species, also widely distributed in the Pacific. Rimelia reticulata is characterized by the effigurately maculate to reticulately-cracked upper cortex, ciliate lobe margins, laciniae with marginal to submarginal soredia, and by the presence of atranorin, chloroatranorin, salazinic acid (major) and consalazinic acid (minor). Apothecia and pycnidia not seen but reported previously (Elix 1994). The species is morphologically variable. Representative specimen examined (total 23). Cook Islands: Rarotonga: Raemaru Track, cliff-face at uppermost section, 2113 S, 15948 W, 280–360 m, on rock, 1998, S. Louwhoff 576 (CANB).
10. Xanthoparmelia subramigera (Gyeln.) Hale This species has been reported as widespread in the tropics, occurring in Central and South America, South Africa, South-East Asia (Hale 1990) and on islands in the Pacific Ocean (Elix & McCarthy 1998). Xanthoparmelia subramigera is characterized by the yellow-green, moderately adnate thallus with subglobose, simple or branched isidia, the pale brown to almost black lower cortex, and by the presence of usnic acid, fumarprotocetraric acid (major), succinprotocetraric acid (major), protocetraric acid (minor) and physodalic acid. Although Hale (1990) considered the presence of succinprotocetraric acid as variable, specimens from Rarotonga consistently produced a significant amount of this substance. Apothecia and pycnidia not seen but reported previously (Hale 1990). Representative specimen examined (total 6). Cook Islands: Rarotonga: Taputarangi Track, 2112 S, 15948 W, 160 m, on rock, 1998, J. A. Elix 42760 (CANB). Patrick McCarthy’s company in the field, as well as much appreciated advice on this paper and related discussions, are gratefully acknowledged. Thanks are also extended to Gerald McCormack from the Cook Islands Natural Heritage Project for accompanying us in the field and providing background information; to Judy Wardlaw for assistance with HPLC, to Alex Crathern for assistance with TLC and to the referees for helpful comments. We would also like to thank the Australian Research Council for their generous financial support. R Culberson, C. F. (1972) Improved conditions and new data for the identification of lichen products by a standardized thin-layer chromatographic method. Journal of Chromatography 72: 113–115. Culberson, C. F. & Johnson, A. (1982) Substitution of methyl tert-butyl ether for diethyl ether in the standardized thin-layer chromatographic method for lichen products. Journal of Chromatography 238: 83–87.
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Culberson, C. F., Culberson, W. L. & Johnson, A. (1981) A standardized TLC analysis of -orcinol depsidones. Bryologist 84: 16–29. Elix, J. A. (1994) Bulbothrix, Canoparmelia, Parmotrema and Xanthoparmelia. Flora of Australia 55: 13–312. Elix, J. A. & Ernst-Russell, K. D. (1993) A Catalogue of Standardized Thin Layer Chromatographic Data and Biosynthetic Relationships for Lichen Substances. 2nd Edn. Canberra: Australian National University. Elix, J. A. & McCarthy, P. M. (1998) Catalogue of the lichens of the smaller Pacific islands. Bibliotheca Lichenologica 70: 1–361. Elix, J. A., Johnston, J. & Verdon, D. (1986) Canoparmelia, Paraparmelia and Relicinopsis, three new genera in the Parmeliaceae (lichenised Ascomycotina). Mycotaxon 27: 271–282. Elix, J. A., Johnston, J. & Parker, J. L. (1988) A computer program for the rapid identification of lichen substances. Mycotaxon 31: 89–99. Feige, G. B., Lumbsch, H. T., Huneck, S. & Elix, J. A. (1993) The identification of lichen substances by a standardized high-performance liquid chromatographic method. Journal of Chromatography 646: 417–427. Hale, M. E. (1965) A monograph of Parmelia subgenus Amphigymnia. Contributions from the United States National Herbarium 36: 193–385. Hale, M. E. (1990) A synopsis of the lichen genus Xanthoparmelia (Vainio) Hale (Ascomycotina, Parmeliaceae). Smithsonian Contributions to Botany 74: 204–205. Louwhoff, S. H. J. J. & Elix, J. A. (1998) The lichen family Parmeliaceae (Ascomycotina) on Lord Howe Island, Australia. Mycotaxon 68: 429–463. McCarthy, P. M. (2000) The lichens of Rarotonga, Cook Islands, South Pacific Ocean I: pyrenocarpous taxa. Lichenologist 32: 15–47. McCormack, G. & Künzle, J. (1991) Rarotonga’s Cross-island Walk. Cook Islands Natural Heritage Project: Prime Minister’s Department, Cook Islands. Merlin, M. D. (1985) Woody vegetation in the upland region of Rarotonga, Cook Islands. Pacific Science 39: 81–99. Mueller-Dombois, D. & Fosberg, F. R. (1998) Vegetation of the Tropical Pacific Islands. New York: Springer-Verlag. Accepted for publication 12 June 1999
THE LICHENS OF RAROTONGA, COOK ISLANDS, SOUTH PACIFIC OCEAN II: PARMELIACEAE Simone H. J. J. LOUWHOFF* and John A. ELIX*
Abstract: Ten parmelioid taxa in five genera were identified from Rarotonga, Cook Islands, South Pacific Ocean. These comprise: three species of Bulbothrix, one species of Canoparmelia, four species of Parmotrema, one species of Rimelia and one species of Xanthoparmelia. Canoparmelia rarotongensis Louwhoff & Elix is described as new, being distinguished from other species of this genus by its unique secondary chemistry (lecanoric acid) and conspicuous, inflated isidia. The majority of parmelioid lichens on Rarotonga have cosmopolitan and pantropical distributions. Bulbothrix is reported for the first time from the Polynesian region. 2000 The British Lichen Society
Introduction Rarotonga is the largest and the highest (653 m) of the Cook Islands, and is situated between latitudes 2112 –15 S and longitudes 15944 –50 W, in the South Pacific Ocean. The island is estimated to be 2 million years old and was formed during a series of volcanic eruptions (McCormack & Künzle 1991). Mueller-Dombois & Fosberg (1998) and Merlin (1985) provided a detailed discussion on the vegetation of the Cook Islands. An introduction to the geology, landforms, vegetation and lichenological history of the island has been provided by McCarthy (2000). The lichen family Parmeliaceae is well-represented in the Southern Hemisphere, but our knowledge of the distribution of parmelioid lichens across the Pacific is limited (Elix & McCarthy 1998). About 150 parmelioid taxa in 25 genera are currently reported for the smaller Pacific Islands (Elix & McCarthy 1998; Louwhoff & Elix 1998). This paper includes a key to the Parmeliaceae of Rarotonga, brief comments on the species, and a description of the new species Canoparmelia rarotongensis. As such, it is the first comprehensive treatment of the family Parmeliaceae in the region, as only Parmotrema cristiferum was reported from Rarotonga previously. Materials and Methods More than 150 specimens of Parmeliaceae were collected from a variety of habitats on Rarotonga and were subsequently examined using morphological and chemical characteristics. Chemical constituents were identified by thin layer chromatography (Culberson, 1972; Culberson et al. 1981; Culberson & Johnson 1982; Elix & Ernst-Russell 1993; Elix et al. 1988), and high performance liquid chromatography (Feige et al. 1993). *Chemistry Department, The Faculties, Australian National University, Canberra 0200, A.C.T., Australia. 0024–2829/00/010049+07 r35.00/0
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Results Ten species in five genera were recognized among Rarotongan collections of Parmeliaceae. Parmotrema cristiferum, P. tinctorum and Rimelia reticulata are common lichens in many regions of the world and are also widespread across the Pacific (Elix & McCarthy 1998). Parmotrema endosulphureum, Bulbothrix isidiza, B. goebelii and B. tabacina are pantropical species, and their distribution in the Pacific region is limited (Elix & McCarthy 1998). The genus Bulbothrix has not been encountered previously in the Polynesian region.
Key to the Parmeliaceae of Rarotonga 1
Lower surface erhizinate at lobe margins . . . . . . . . . . . . . 2 Lower surface rhizinate to lobe margins . . . . . . . . . . . . . . 6
2(1)
Lobes narrow (2–4 mm wide); lower surface with a narrow (up to 10 mm wide), erhizinate marginal zone . . . . . . . . . . . . . . . . . . Canoparmelia rarotongensis Lobes broad (5–20 mm wide); lower surface with a broad (up to 10 mm wide) erhizinate marginal zone . . . . . . . . . . . . . 3
3(2)
Thallus sorediate; medulla K+yellow then red; salazinic acid present . . . . . . . . . . . . . . . . . . . . . Parmotrema cristiferum Thallus isidiate; medulla K; salazinic acid absent . . . . . . . 4
4(3)
Medulla pale orange-yellow; C+pink; gyrophoric acid present . . . . . . . . . . . . . . . . . Parmotrema endosulphureum Medulla white, Cor C+red; gyrophoric acid absent . . . . . . 5
5(4)
Medulla . . . Medulla . . .
6(1)
Upper cortex effigurately maculate to reticulately cracked; thallus sorediate . . . . . . . . . . . . . . . . . . . Rimelia reticulata Upper cortex emaculate or faintly maculate; thallus isidiate . . . 7
7(6)
Cortex K; usnic acid present; lobe margins eciliate . . . . . . . . . . . . . . . . . . Xanthoparmelia subramigera Cortex K+yellow; usnic acid absent; lobe margins with bulbate cilia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
8(7)
Medulla K, C+pink; gyrophoric acid present . . . . . . . . . . . . . . . . . . . . . . . . Bulbothrix goebellii Medulla K+yellow then red; salazinic acid present . . . . . . . . 9
9(8)
Lower cortex black . . . . . . . . . . . . . . Bulbothrix tabacina Lower cortex pale . . . . . . . . . . . . . . . . Bulbothrix isidiza
C+red; lecanoric acid present; lobesflat . . . . . . . . . . . . . . . . . . Parmotrema tinctorum C; protocetraric acid present; lobesfolded . . . . . . . . . . . . . . . . Parmotrema saccatilobum
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The Species 1. Bulbothrix goebelii (Zenker) Hale This species is finer than either of the other two taxa in this genus described from Rarotonga, with narrow (0·5–1·5 mm wide) lobes, a black lower cortex, atranorin and chloroatranorin in the cortex, and gyrophoric acid (major) and lecanoric acid (trace) in the medulla. Apothecia and pycnidia not seen but the former have been reported previously (Elix 1994). Specimens collected appeared to belong to one of two categories, fine-lobed or broader-lobed. These are not recognized as different taxa and are simply referred to as different morphotypes of B. goebelii. All three Bulbothrix species recognized from Rarotonga are isidiate and pantropical in distribution. Representative specimens examined (total 14): Cook Islands: Rarotonga: Muri Lagoon, near mouth of Avana stream, 2115 S, 15944 W, 1 m, on trees above beach, 1998, J. A. Elix 42712 (CANB); Raemaru Track, 2114 S, 15949 W, 100–200 m, in fernland encroaching upon Albizzia/Allocasuarina forest, on Albizzia, 1998, S. Louwhoff 571 (CANB).
2. Bulbothrix isidiza (Nyl.) Hale Only one specimen of this species was collected on Rarotonga. This species has atranorin and chloroatranorin in the cortex, salazinic acid (major) and consalazinic acid (minor) in the medulla, and a pale lower cortex. Apothecia and pycnidia not seen but reported previously (Elix 1994). In the Pacific it was previously reported for the Hawaiian Islands (Elix & McCarthy 1998). Specimen examined. Cook Islands: Rarotonga: Te Rua Manga Track, climb to the base of Te Rua Manga (The Needle), 2114 S, 15946 W, c. 250 m, corticolous in slope forest with native tree species Pittosporum and Weinmannia, 1998, S. Louwhoff 615 (CANB).
3. Bulbothrix tabacina (Mont. & Bosch) Hale This species is characterized by the presence of atranorin and chloroatranorin in the cortex, salazinic acid (major) and consalazinic acid (minor) in the medulla, and by the black lower cortex. The latter sets it apart from B. isidiza (see above). Some specimens collected on Rarotonga were broader than usual (10 mm cf. 1·5–5 mm wide) and occasionally displayed marginal lobules. Apothecia not seen but reported previously (Elix 1994). Pycnidia, not previously reported (Elix 1994), were observed to be sparse on three specimens; conidia rod-shaped to elongate-unciform, (4·5–)5–7·5(–8)1 m. Representative specimen examined (total 29): Cook Islands: Rarotonga: Raemaru Track, steep slope to summit cliff, 2113 S, 15948 W, 200 m, on Paraserianthes falcataria in disturbed forest, 1998, S. Louwhoff 563 (CANB).
4. Canoparmelia rarotongensis Louwhoff & Elix, sp. nov. Species cum thallo ut in Canoparmelia owariensis sed ab hac specie thallo corticolo, laxe adnato, isidiis apicibus non erumpentibus et acido lecanorico continente differt. Typus: Cook Islands, Rarotonga, Muri Lagoon, 2115 S, 15944 W, 1 m, on Hibiscus along the foreshore, 6 June 1998, J. A. Elix 42730 (Holotypus—CANB).
(Fig. 1)
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F. 1. Holotype of Canoparmelia rarotongensis (J. A. Elix 42730 in CANB). Scale in millimetres.
Thallus moderately adnate, membranaceous, up to 6 cm wide. Lobes irregular,contiguous and contorted centrally,constricted at base of apices, where lobes become separated, 2–4 mm wide; margins entire, occasionally becoming subcrenate, mainly flat, eciliate. Upper surface pale, dusty grey-green, emaculate, irregularly cracked centrally, isidiate; isidia consistently conspicuously inflated, mostly branched, each isidiate cluster up to 0·5 mm wide and up to 0·8(–1) mm high, predominantly laminal. Medulla white. Lower surface black, dull, with a pale brown, narrow (up to 1 mm wide) erhizinate marginal zone; rhizines black, sparse to moderately dense, coarse, simple. Apothecia and pycnidia not seen. Chemistry. Cortex K+yellow; medulla K, C+red, PD; containing atranorin, chloroatranorin, lecanoric acid (major), orsellinic acid (trace), orcinol (trace). Canoparmelia rarotongensis is known only from the type collection, where it occurred on Hibiscus in a coastal site. Notes. The new species is characterized by the conspicuous isidia, which are consistently inflated, branched, but which do not become sorediate, and by the presence of atranorin and chloroatranorin in the cortex, and lecanoric acid in the medulla. The new species can be readily distinguished from other species of Canoparmelia by the above characteristics (Elix 1994; Elix et al.
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1986). Lecanoric acid has not previously been detected in this genus. Only three species of Canoparmelia, C. caroliniana, C. scrobicularis and C. texana, have been reported for the Pacific region (Elix & McCarthy 1998). The new species is morphologically and chemically distinct from these, and has been named for its type locality. 5. Parmotrema cristiferum (Taylor) Hale This species has a cosmopolitan distribution (but is absent from Europe) and is known to be widespread in the Pacific region. Apothecia and pycnidia not seen but the former have been reported previously (Elix 1994). It is a morphologically variable species characterized by sorediate lobes, and by the presence of atranorin, chloroatranorin, salazinic acid (major), consalazinic acid (minor) and eumitrin A1 (trace). Representative specimen examined (total 19): Cook Islands: Rarotonga: Taputarangi Track, in slope forest, 2112 S, 15948 W, 160 m, on twig, 1998, J. A. Elix 42771 (CANB).
6. Parmotrema endosulphureum (Hillm.) Hale Although Parmotrema endosulphureum has been reported for North, Central and South America, and for East Africa (Hale 1965), in the Pacific region it has only been recorded from Fiji (Hale 1965), the Cocos Islands (Costa Rica) and the Galapagos Islands (Elix & McCarthy 1998). Parmotrema endosulphureum is isidiate, has atranorin and chloroatranorin in the cortex, and gyrophoric acid and the eumitrin N complex in the medulla, the latter being responsible for the pale orange-yellow colouration of the medulla. Apothecia and pycnidia not seen but the former have been reported previously (Hale 1965). Representative specimen examined (total 2). Cook Islands: Rarotonga: Te Ko’u Track, near taro plantations, 2113 S, 15946 W, 100 m, on rock, 1998, J. A. Elix 42822 (CANB).
7. Parmotrema saccatilobum (Taylor) Hale This species primarily has a South-East Asian distribution, but is also widespread across the Pacific, with the type collected from Pitcairn Island. It is characterized by a large, loosely attached thallus, folded lobes, isidia, and by the presence of atranorin, chloroatranorin and protocetraric acid. This species was morphologically quite variable on Rarotonga. One specimen was observed to produce pycnidia, not previously reported for this species (Elix 1994); the conidia were found to be elongated filiform, 7–121 m. One specimen was fertile, although the spores were slightly longer than usually reported [30 cf. 22–26 m (Hale 1965)]. Representative specimen examined (total 13). Cook Islands: Rarotonga: Te Ko’u Track, taro plantations in Takuva’ine Valley, 2113 S, 15946 W, 60–100 m, on boulders in disturbed habitat, 1998, S. Louwhoff 529 (CANB).
8. Parmotrema tinctorum (Despr. ex Nyl.) Hale This is a cosmopolitan species that is also widespread across the Pacific. Parmotrema tinctorum is morphologically variable, but can be recognized by the
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large thallus, isidiate, broad lobes (up to 2–2·5 cm wide), and by the presence of atranorin, chloroatranorin and lecanoric acid (traces of orsellinic acid and orcinol). Apothecia and pycnidia not seen but reported previously (Elix 1994). Representative specimen examined (total 40). Cook Islands: Rarotonga: at the mouth of Avana stream, 2114 S, 15943 W, 1 m, on seashore trees (Hibiscus and palm), 1998, J. A. Elix 42991 (CANB).
9. Rimelia reticulata (Taylor) Hale & A. Fletcher A very common, cosmopolitan species, also widely distributed in the Pacific. Rimelia reticulata is characterized by the effigurately maculate to reticulately-cracked upper cortex, ciliate lobe margins, laciniae with marginal to submarginal soredia, and by the presence of atranorin, chloroatranorin, salazinic acid (major) and consalazinic acid (minor). Apothecia and pycnidia not seen but reported previously (Elix 1994). The species is morphologically variable. Representative specimen examined (total 23). Cook Islands: Rarotonga: Raemaru Track, cliff-face at uppermost section, 2113 S, 15948 W, 280–360 m, on rock, 1998, S. Louwhoff 576 (CANB).
10. Xanthoparmelia subramigera (Gyeln.) Hale This species has been reported as widespread in the tropics, occurring in Central and South America, South Africa, South-East Asia (Hale 1990) and on islands in the Pacific Ocean (Elix & McCarthy 1998). Xanthoparmelia subramigera is characterized by the yellow-green, moderately adnate thallus with subglobose, simple or branched isidia, the pale brown to almost black lower cortex, and by the presence of usnic acid, fumarprotocetraric acid (major), succinprotocetraric acid (major), protocetraric acid (minor) and physodalic acid. Although Hale (1990) considered the presence of succinprotocetraric acid as variable, specimens from Rarotonga consistently produced a significant amount of this substance. Apothecia and pycnidia not seen but reported previously (Hale 1990). Representative specimen examined (total 6). Cook Islands: Rarotonga: Taputarangi Track, 2112 S, 15948 W, 160 m, on rock, 1998, J. A. Elix 42760 (CANB). Patrick McCarthy’s company in the field, as well as much appreciated advice on this paper and related discussions, are gratefully acknowledged. Thanks are also extended to Gerald McCormack from the Cook Islands Natural Heritage Project for accompanying us in the field and providing background information; to Judy Wardlaw for assistance with HPLC, to Alex Crathern for assistance with TLC and to the referees for helpful comments. We would also like to thank the Australian Research Council for their generous financial support. R Culberson, C. F. (1972) Improved conditions and new data for the identification of lichen products by a standardized thin-layer chromatographic method. Journal of Chromatography 72: 113–115. Culberson, C. F. & Johnson, A. (1982) Substitution of methyl tert-butyl ether for diethyl ether in the standardized thin-layer chromatographic method for lichen products. Journal of Chromatography 238: 83–87.
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