Lecanora leprosa and L. sulphurescens are two commonly misidentified pantropical lichens. A detailed circumscription is presented to help overcome such difficulties. Both species contain a chemosyndrome of chlorodepsidones based on gangaleoidin. The new depsidone chlorolecideoidin (methyl 2,4,9-trichloro-3,8-dihydroxy-1,6-dimethyl-11-oxo-11H-dibenzo[b,e][1,4]-dioxepin- 7-carboxylate) has been shown to be a minor component of both species.Lecanora leprosa und L. sulphurescens sind zwei häufig fehlbestimmte pantropische Flechten. Eine ausführliche Beschreibung der beiden Arten wird vorgelegt. Beide Arten enthalten ein auf Gangaleoidin basierendes Chemosyndrom von Chlordepsidonen. Das neue Depsidon Chlorlecideoidin (Methyl 2,4,9-Trichlor-3,8-dihydroxy-1,6-dimethyl-11-oxo-11Hdibenzo[ b,e][1,4]-dioxepin-7-carboxylat) wird beschrieben. Es kommt in beiden Arten als Nebeninhaltsstoff vor

Elix, John A.

Lumbsch, Helge Thorsten

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71Tropical Bryology 7: 71-75, 1993Notes on the circumscription of the lichens Lecanora leprosa andL. sulphurescens (Lecanoraceae, lichenised Ascomycotina)H. Thorsten Lumbsch* and John A. Elix***Universität Essen, Fachbereich 9/Botanik, Postfach 103 764, D-4300 Essen 1, Germany**Chemistry Department, Australian National University, Canberra, ACT 0200, AustraliaAbstract. Lecanora leprosa and L. sulphurescens are two commonly misidentified pantropicallichens. A detailed circumscription is presented to help overcome such difficulties. Both speciescontain a chemosyndrome of chlorodepsidones based on gangaleoidin. The new depsidone chloro-lecideoidin (methyl 2,4,9-trichloro-3,8-dihydroxy-1,6-dimethyl-11-oxo-11H-dibenzo[b,e][1,4]-dio-xepin-7-carboxylate) has been shown to be a minor component of both species.Zusammenfassung.  Lecanora leprosa und L. sulphurescens sind zwei häufig fehlbestimmtepantropische Flechten. Eine ausführliche Beschreibung der beiden Arten wird vorgelegt. Beide Artenenthalten ein auf Gangaleoidin basierendes Chemosyndrom von Chlordepsidonen. Das neueDepsidon Chlorlecideoidin (Methyl 2,4,9-Trichlor-3,8-dihydroxy-1,6-dimethyl-11-oxo-11H-dibenzo[b,e][1,4]-dioxepin-7-carboxylat) wird beschrieben. Es kommt in beiden Arten als Nebenin-haltsstoff vor.The tropical species of the Lecanora subfuscagroup are poorly known. While studying theAustralasian members of this group, we soonrealized that many specimens were misidentifiedwith the collective names L. leprosa or L.sulphurescens. A number of these specimens,however, belong to different, similar species.Lecanora leprosa and L. sulphurescens are des-cribed here in some detail to clarify the circumsc-ription of the species, including the secondarychemistry, which is an important character in thedistinction of these taxa. Moreover, a newsubstance, chlorolecideoidin, was detected inmost specimens of both species and is describedhere.Material and MethodsSpecimens were studied from the following her-baria: B, BRI, C, CBG, COLO, DNA, ESS, G,GZU, H, HO, LD, M, MEL, NSW, PC, PERTH,S, TNS, U, UPNG, UPS, WELT, ZT and the72private herbarium of H.T. Lumbsch (Essen).Microscopy. Thalli and apothecia were cut usinga freezing microtome into sections 16-20 µm inthickness and either examined in situ or stainedwith lactophenol cottonblue.Chemistry. The chemical constituents were iden-tified using thin layer chromatograpy (Culber-son 1972, Culberson et al. 1981, Culberson &Johnson 1982) and high performance liquidchromatography (Feige et al. 1993).Synthesis of Chlorolecideoidin. A solution ofsulphuryl chloride (0.26 ml) in anhydrous dio-xan (25 ml) was added dropwise to a stirredsolution of lecideoidin (0.5 g) in anhydrousdioxan (25 ml) at room temperature, and stirringcontinued for 24h. The solvent was then evapo-rated under reduced pressure and the residuecrystallized from ethyl acetate to give chloroleci-deoidin (45%) as colourless needles, m.p. 234° C(Found: mol. wt, 431.9572 C17H1135ClO7 requiresmol. wt, 431.9570). 1H n.m.r. (CDCl3)  2.41,2.43, 2s, ArMe; 3.85, s, CO2Me; 10.51, s, OH.Mass spectrum m/z 436 (3%), 434 (12), 432 (M,11), 402 (11), 400 (13), 399 (14), 397 (20), 367(15), 365 (27), 339 (7), 337 (10), 325 (10), 187(12), 186 (13), 149 (14), 105 (61), 67 (100).The speciesLecanora leprosa FéeEssai sur les Cryptogames des Écorces ExotiquesOfficinales: 118 (1824). - Type: Brazil, Rio deJaneiro,  Glaziou 1921 (PC-FÉE - neotype,herewith selected).Thallus corticolous, crustose, uniform, adnate,continuous or disperse verrucose to verruculose,yellowish-white to yellowish grey, epruinose.Soredia absent. Margins definite. Prothallusabsent or sometimes whitish-grey.Apothecia immersed when young, later beco-ming sessile, 0.2-0.7 (-1.1) mm diam., discs lightorange to yellowish brown, epruinose or slightlypruinose, margins concolorous with the thallus,thin to thick, entire, sometimes slightly verrucose,later thin to disappearing. Cortex hyaline, moreor less gelatinous, inspersed, distinct, 10-15 µmlaterally, up to 25 µm at base. Amphitheciumwith large, Pol + crystals (=pulicaris typeaccording to Brodo 1984). Parathecium withsmall Pol + crystals, not disappearing in KOH,10-15 µm thick. Epihymenium not pigmented oryellowish pigmented, with small Pol + brightyellow crystals, which disappear in KOH, 10-15µm tall (=chlarotera type according to Brodo1984). Hymenium hyaline, 55-75 µm high.Hypothecium hyaline or yellowish to yellowishbrown. Paraphyses ca. 1.5 µm thick, septate,apically weakly ramified and slightly thickened(up to 2.5 µm). Asci clavate, 50-70 x 10-15 µm,8-spored. Spores narrowly ellipsoid, 9.5-13.5 x5.0-7.0 µm.Chemistry: Atranorin and gangaleoidin as ma-jor; chloroatranorin and norgangaleoidin as minorsubstances and chlorolecideoidin and leoidin intraces.Nomenclature: Here we follow the selection ofthe lectotype by Vainio (1890), who mentionedFée collection no. 1921 as authentic material.Brodo (1984) pointed out that this specimen is apoor choice for a lectotype because the specimenincludes a reference to Fée’s original publica-tion, although it agrees well with the currentconcept of the species. It cannot be considered asa lectotype since it was probably not available toFée when he described the new species. Howe-ver, since apparently no other authentic materialis available, the specimen in PC-Fée is hereselected as neotype of L. leprosa.Lecanora leprosa is a pantropical species. It isvery common in tropical parts of both North andSouth America, Asia (Wei 1991) and in Africa.In Australia, however, it seems to be quite rare.In mangroves in Northern and Eastern AustraliaL. leprosa is replaced by a superficially similarspecies, L. helva Stizenb. The latter differs fromL. leprosa in the rough thallus surface, a blackishprothallus and the presence of the 2'-O-methyl-perlatolic acid instead of the gangaleoidin che-mosyndrome. This species is very common inAustralia, especially in mangroves and has beencommonly misidentified as L. leprosa (e.g. byHafellner et al. 1989). L. helva seems to berestricted to the Southern Hemisphere, where itis known from Southern Africa and Australia.73Other superficially similar corticolous specieswith orange apothecia and yellowish-white toyellowish grey thalli include L. louisianae B. deLesd. and L. subflava Tuck. in Nyl., but thesespecies can be readily distinguished by the pre-sence of chloroxanthones instead of the gangale-oidin chemosyndrome, as well as other morpho-logical characters. These species will discussedin detail elsewhere.Selected specimens examined: Australia - NewSouth Wales: Patonga, sea level, 19.1.1978, N.Stevens (BRI-491272). - Queensland: Brisbane,in the city near the Brisbane River, 27°26’S,153°03’E, 50 m alt., 2.1988, A. & M. Aptroot21704 (hb. Aptroot). - Moreton Bay, Coochie-mudlo Island, W of N Stradbroke Island, 27°38’S,153°19’E, mangrove, 30.8.1984, G.H. Bell 934(AD-22430). - Port Alma, sea level, 10.6.1975,R.W. Rogers 794 (BRI-491674). - Port CurtisDistr., 23°03’S, 151°46’E, 19.1.1985, E. You-man (BRI-476443), Wreck Island, 23°02’S,151°58’E, 16.1.1985, E. Youman 38 (BRI-476440). - Brampton Island, 20°49’S, 149°17’E,8.8.1974,  J.M. Gilbert (HO-62256). - PapuaNew Guinea: Central Province, Motupore Is-land, Bootless Bay, 12 km SE of Port Moresby,9°32’S, 147°16’E, 1 m alt., 22.2.1987, H. Sip-man 21830, 21853 (B). - Cook Island: Maunga-tea Mtn., 6.1929, H.E. Parks & S.T. Parks 22548e(COLO-S-18215). - Tonga: Tongatabu Island,6.1926,  W.A. Setchell 45 (COLO-S-18218). -Moçambique: Sul do Save, Distr. LourençoMarques, 8 km E of Impamputo, 18.10.1953, O.Almborn 7038 (LD), Botanical Garden in Lou-renço Marques, 19.10.1953, O. Almborn 7189(LD). - Tanzania: Mountain between Moshi andHimo, ca. 900 m alt., 17.12.1978, Schüz (STU).- South Africa: Natal, Distr. Inanda, UmhlangaRocks, 14.11.1953, O. Almborn 9715 (LD). USA- Hawaii: Oahu, Waianae Mts, Kolekole Pass,1600 ft., 22.6.1979, C.W. Smith 4786 (hb.Lumbsch).Lecanora sulphurescens FéeBull. Soc. Bot. Fr. 20: 313 (1873). - Type: Brazil,Rio de Janeiro, Glaziou 3850 (UPS - lectotype).Thallus saxicolous, crustose, uniform, adnate,continuous or rimose-areolate, yellowish-whiteto yellowish grey, epruinose. Soredia absent.Margins definite. Prothallus absent.Apothecia immersed when young, later subim-mersed to slightly sessile, 0.3-0.6 (-1.1) mmdiam., discs light orange to yellowish brown,epruinose or slightly pruinose, margins concolo-rous with the thallus, thin to thick, entire. Cortexhyaline, more or less gelatinous, inspersed, di-stinct, 10-15 µm laterally, up to 20 µm at base.Amphithecium with large, Pol + crystals (=puli-caris type according to Brodo 1984). Parathe-cium with small Pol + crystals, disappearing inKOH, 10-15 µm thick. Epihymenium orangebrown to olive brown pigmented, with small Pol+ bright yellow crystals also present in the upperparts of the hymenium which do not disappear inKOH, 15-20 µm tall. Hymenium hyaline, 60-75µm high. Hypothecium hyaline. Paraphyses ca. 2µm thick, septate, apically weakly ramified andslightly thickened (up to 3.0 µm). Asci clavate,40-55 x 10-17.5 µm, 8-spored. Spores ellipsoidto narrowly ellipsoid, 10.0-13.5 x 5.5-7.5 µm.Chemistry: Atranorin, gangaleodin and leoidinas major; chloroatranorin as minor substanceand chlorolecideoidin as well as unidentifiedfatty acids in traces.Lecanora sulphurescens is characterized by thesubimmersed apothecia, the constant presence ofthe gangaleoidin chemosyndrome and the saxi-colous habitat, as well as the epihymenium withsmall KOH-insoluble crystals and pulicaris-typeamphithecium. Vänskä (1986) placed L. depres-sa Fée into synonymy with L. sulphurescens. Theholotype of L. depressa (Brazil, Rio de Janeiro,Glaziou 3293b, C-lectotype, selected by Vänskä1986), however, differs in having dark brown,completely immersed, discs as well as in lackingthe gangaleoidin chemosyndrome, and istherefore considered to be a different species.The morphologically similar L. plumosa Müll.Arg. seems to be restricted to Australia. Thislatter species, however, differs in having sessile,non-immersed apothecia and the presence of the2'-O-methylperlatolic acid chemosyndrome in-stead of gangaleoidin. For the synonymy of L.sulphurescens see Lumbsch (1992).74Lecanora sulphurescens has a pantropical distri-bution and is known from Africa, South Americaand Australasia. It seems to be rather rare inAustralia.Selected specimens examined: Australia - Qu-eensland: Jim Crow Mtn., 25 km NE of Rock-hampton, 23°13’S, 150°38’E, 200-300 m alt.,14.2.1986, G. Rambold 4475, 4483 (M). - Thurs-day Island (NSW L-4410). - Papua New Gui-nea: Central Province, Varirata Plateau, 22 kmE of Port Moresby, 9°27’S, 147°23’E,3.1987, A.Aptroot 19041 (hb. Aptroot). - Cape VerdeIslands: São Tiago, Rui Vaz, ca. 630 m alt.,12.10.1986,  B. Mies 209c, CV-1041 (hb.Lumbsch).The new substance: ChlorolecideoidinThe HPLC retention time of the new substancepresent in L. leprosa and L. sulphurescens indi-cated that this compound was more hydrophobicthan gangaleoidin but less hydrophobic thanleoidin. Given that this new compound wasbiosequentially related to these substances, O-methylgangaleoidin or chlorolecideoidin seemedthe most likely possibilities. Chromatographiccomparisons of extracts of these lichens with asynthetic sample of O-methylgangaldeoidin(Sargent et al. 1975) established that this com-pound was dissimilar to the unknown lichensubstance. Subsequently we have undertaken thesynthesis of chlorolecideoidin and found that theTLC and HPLC behaviour of this compound tobe identical with that of the minor, new metabo-lite present in these lichens.Chlorolecideoidin was prepared by chlorinationof lecideoidin (Chester et al. 1979) with sulphu-ryl chloride as described above. The standardi-zed chromatographic data for these compoundsare listed in Table 1.Acknowledgements: The authors are grateful to the curators ofthe cited herbaria for sending us material in their care forexamination.LiteratureBrodo, I. M. 1984. The North American species of the Leca-nora subfusca group. Beiheft zur Nova Hedwigia 79:63-185.Chester, D.O., J.A. Elix & A.J. Jones 1979. Lecideoidin and3'-dechlorolecideoidin. New depsidones from anAustralian Lecidea (lichen). Australian Journal ofChemistry 32: 1857-1861.Culberson, C. F. 1972. Improved conditions and new data forthe identification of lichen products by a standardizedthin-layer chromatographic method. Journal of Chro-matography 72: 113-125.Culberson, C. F. & A. Johnson. 1982. Substitution of methyltert.-butyl ether for diethyl ether in standarzided thin-layer chromatographic method for lichen products.Journal of Chromatography 238: 438-487.Culberson, C. F., W. L. Culberson & A. Johnson. 1981. Astandarized TLC analysis of -orcinol depsidones.Bryologist 84: 16-29.Feige, G. B., H. T. Lumbsch, S. Huneck & J. A. Elix. 1993.The identification of lichen products by a standardizedhigh-performance liquid chromatographic method.Journal of Chromatography, in press.Hafellner, J., R. B. Filson & R. W. Rogers. 1989. Somegenera and species of lichenized fungi new to Austra-lia. Nova Hedwigia 48: 229-235.Lumbsch, H. T. 1992. Lecanora argentea Oxner & Volkova,the correct name for L. fuliginosa Brodo, and com-ments on related species. Bryologist 95: 430-432.Sargent, M.V., P. Vogel & J.A. Elix 1975. Structure of thelichen depsidone gangaleoidin. Journal of the Chemi-cal Society, Perkin Transactions I, 1975: 1986-1991.Vainio, E. A. 1890. Étude sur la classification naturelle et lamorphologie des lichens du Brésil. I. Acta SocietatisFauna et Flora Fennicae 7: 1-247.Vänskä, H. 1986. Lecanora vainioi and L. ahtii, two newlichen species from Brazil, compared with five alliedspecies. Annales Botanici Fennici 23: 121-141.Wei, Jiang-chun. 1991. An enumeration of lichens in China.278 pages. Beijing.

Notes on the circumscription of the lichens Lecanora leprosa and L. sulphurescens (Lecanoraceae, lichenised Ascomycotina)

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