A New Species in the Lecanora Subfusca Group

Lichenologist 27(3): 161-167 (1995)

A NEW SPECIES IN THE LECANORA SUBFUSCA GROUP CONTAINING USNIC ACID IN ADDITION TO ATRANORIN H. Thorsten LUMBSCH* Abstract: Lecanora pseudogangaleoides spec. nov. is a saxicolous lichen in southeastern Australia. It fits anatomically into the L. subfusca group (=Lecanora s.str.), but differs from most previous concepts of that group in containing usnic acid in addition to atranorin. The presence of usnic acid is now considered to be of less importance in that group, and species containing usnic acid may well belong to Lecanora s.str. Within L. pseudogangaleoides chemical variation with respect to the presence of xanthones was observed and two subspecies are distinguished. Lecanora pseudogangaleoides s.str. lacks xanthones, whereas L. pseudogangaleoides subsp.

verdonii subsp. nov. contains the arthothelin chemosyndrome in addition to the normal occurrence of the psoromic acid chemosyndrome. A key for the distinction of L. pseudogangaleoides and similar species is included.

Introduction The presence or absence of lichen substances can be important correlative characters in the circumscription of genera, especially of predominantly foliose and fruticose lichens. Well-known examples include Phaeophyscia and Physcia (Moberg 1977), and Bulbothrix and Relicina (Hale 1976). Among crustose lichen families examples are less obvious, but with the current trend of denning smaller natural units in crustose groups, some genera are also chemically well denned, such as Miriquidica with predominantly miriquidic acid (Hertel & Rambold 1987) or Haematomma s. str. with haematommone (Huneck et al. 1991). Within the large and heterogeneous genus Lecanora, the L. subfusca group {-Lecanora s.str.) is characterized by the presence of atranorin (Brodo 1984). Sometimes the group is restricted to species lacking usnic acid (Obermayer & Poelt 1992; Lumbsch 1994). Usnic acid, on the other hand, is the characteristic secondary metabolite of the Straminella group. Therefore, it at first seemed remarkable when Brodo & Elix (1993) placed L. jamesii close to L. chlarotera, even though it contained both usnic acid and atranorin, along with an additional corticolous, not formally described taxon from Florida, which contained usnic acid and only traces of atranorin. During a taxonomic revision of species belonging to the L. subfusca group s. str. in Australasia, it became apparent that a number of species occur in the region that are anatomically related to the L. subfusca group, but differ in containing usnic acid as a major compound. Among these are at least two saxicolous species, L. wilsonii Mull. Arg. and a new species, common in eastern Australia, which is described below. *Botanisches Institut, Universitat Essen, D-45117 Essen, Germany. 0024-2829/95/030161+07 808.00/0

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Materials and Methods Specimens were studied from the following herbaria: BRI, CBG, G, GZU, MEL, STU, and the private herbaria of PD Dr Klaus Kalb (Neumarkt/Opf.), Dr H. Mayrhofer (Graz) and H. T. Lumbsch. Apothecia sections were cut using a freezing microtome at 16-20 pm thickness and stained with lactophenol cotton blue. The chemical constituents were identified using thin layer chromatography, TLC (Culberson 1972; Culberson & Johnson 1982) and gradient-elution high performance liquid chromatography, HPLC (Feige et al. 1994).

Results and Discussion Lecanora pseudogangaleoides Lumbsch spec. nov. Planta saxicola. Thallus crustaceus, uniformis, adnatus, rimoso-areolatus usque ad verruculosus vel verrucosus, luteo-griseus vel viridulo-griseus, epruinosus. Soredia nulla. Prothallus nigrofuscus. Apothecia sessilia, 0-5-1-3 mm in diametro, disci atro-brunnei vel rubrofusci, epruinosi. Margines apotheciorum luteo-grisei, tenue, laeves. Cortex hyalinus, inspersus, lateraliter 1020 nm, basaliter 15-25 um. Amphithecium crystalla magna minutaque continens. Parathecium hyalinum, crystalla minuta continente, c. 15 um crassum. Epihymenium olivaceobrunneum, egranulosum, c. 10-15 um altum. Hymenium hyalinum. Hypothecium et subhymenium hyalinum. Paraphyses c. 1-5 um crassae. Asci clavati, octospori. Sporae hyalinae, non-septatae, late ellipsoideae vel ellipsoideae, 10-5-14-5 x 6-5-9-0 um. Typus: Australia, Australian Capitol Territory, W slopes of Black Mtn, Canberra, 730 m, 14 August 1977, J. A. Elix 3641 (CBG—holotype).

(Fig. 1). Thallus thin to rather thick, 0-3-0-8 mm, plane to slightly convex, rimose to verruculose or verrucose, yellowish grey to greenish grey, sometimes yellowish green, epruinose. Soredia absent. Prothallus blackish brown. Apothecia sessile, 0-5-1-3 mm in diam.; disc blackish brown to dark red-brown or red-brown, epruinose; apothecial margin concolorous with thallus, thin, smooth, entire; parathecium sometimes visible as a dark-brown parathecial ring. Cortex hyaline, inspersed with small crystals, 10-20 jum laterally, 15-25 jim basally. Amphithecium with large crystals that do not dissolve in K, but small crystals rapidly dissolving in K are also present. Parathecium hyaline, with crystals insoluble in K, 15 pun thick. Epihymenium olivaceous brown, pigmentation altered to greenish brown by K, without crystals, c. 10-15 um high. Hymenium hyaline. Hypothecium and subhymenium hyaline. Paraphyses c. 1-5 p thick, apically slightly reticulate and slightly thickened (up to 2-5 um), with olivaceous apical caps. Asci clavate, 8-spored. Ascospores broadly ellipsoid to ellipsoid, 10-5-14-5 x 6-5-9-0 um. Chemistry: Major substances: atranorin, psoromic acid and usnic acid. and 2'-O-demethylpsoromic acid. Minor iviinor substances: suosiances: chloroatranorin cnioroa Yontlinnpc nrpcpnt r\r ahcpnt Xanthones present or absent. Etymology: The epithet refers to the superficial morphological similarity of the new species with L. gangaleoides.

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FIG. 1. Lecanora pseudogangaleoides. A & B, L. pseudogangaleoides s.str. A, part of the holotype (CBG); B, BRI-475702, C. & D, L. pseudogangaleoides subsp. verdonii. C, Mayrhofer 3407 (hb. Mayrhofer); D, Mayrhofer 6698 (GZU). Scale= 1 mm.

Notes: Lecanora pseudogangaleoides is chemically characterized by the presence of usnic acid in addition to atranorin and the psoromic acid chemosyndrome. Anatomically it can be recognized by the broadly ellipsoid spores, the presence of large and small crystals in the amphithecium, and the olivaceous epihymenium, which turns greenish brown in K. Some collections of L. pseudogangaleoides with light apothecial discs come rather close to L. wilsonii Mull. Arg., which differs, however, in lacking the psoromic acid chemosyndrome; it contains usnic acid as the major compound, atranorin as a submajor compound and chloroatranorin in traces. Moreover, it can be distinguished from L. pseudogangaleoides by a reddish brown epihymenium that does not alter its colour in K, the apothecial discs are lighter, being red-brown to orange-brown, and the prothallus is whitish grey.

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The Australian endemic L. margarodes (Korber) Nyl. (syn. L. continua Knight) is also a variable species and some morphotypes might be confused with L. pseudogangaleoid.es. However, L. margarodes is readily distinguished by the presence of crystals in the epihymenium and in containing pannarin, but lacking psoromic and usnic acids (Lumbsch 1994). Another morphologically similar species is L. gangaleoides Nyl., which also occurs in Australia (Lumbsch 1994). This cosmopolitan species, however, is readily distinguished by the absence of usnic acid, the presence of gangaleoidin instead of psoromic acid, the darker apothecial discs, and a thicker thallus. The chemistry of L. gangaleoides has been described by Devlin et al. (1986), whose results were confirmed by Lumbsch (1992), who found that the presence of leoidin and skyrin varies in that species. Purvis et al. (1992) mentioned norsticitic, stictic and thiophanic acids in addition, but this could not be confirmed in our laboratory. Ecology and distribution: Lecanora pseudogangaleoides inhabits exposed acidic

rocks, mostly sandstone or granite, in areas of moderate rainfall in the hinterland ranges of southern and eastern Australia. These areas are characterized by dry sclerophyllous Eucalyptus forests. However, it can also be found in open situations of wet sclerophyllous forests in eastern Australia. Associated species include Buellia spp., Parmotrema reticulatum (Taylor) Choisy, Pertusaria persulphurata Mull. Arg., Teloschistes spinosus (Hook. f. & Taylor)

J. Murray, and Xanthoparmelia spp. Variation: Lecanora pseudogangaleoides is a rather variable species with regard

to its morphology and the colouration of the apothecial discs. Whereas most collections have a rather thin and rimose-areolate to verruculose thallus, other specimens exhibit a verrucose and rather thick thallus. Whereas several specimens have dark-brown to blackish brown discs, others have red-brown discs. Since no correlative characters were found, and the variation formed a continuum, these are interpreted as infraspecific variations. With regard to chemistry, two chemotypes can be distinguished by the presence or absence of the arthothelin chemosyndrome. Whereas most examined specimens contained the atranorin- and psoromic acid chemosyndrome, as well as usnic acid, some specimens contained the arthothelin chemosyndrome in addition. No anatomical characters were found that correlate with these chemical differences and thus they are accepted here at a subspecific level following the proposals of others working in the genus Lecanora (Imshaug & Brodo 1966; Leuckert & Poelt 1989; Lumbsch et al. 1994). Thus the following two subspecies can be distinguished. Lecanora pseudogangaleoides subsp. pseudogangaleoides Chemistry: K+yellow, KC+yellow, C —, PD+yellow; major substances: atranorin, psoromic and usnic acids. Minor substances: chloroatranorin and 2'-O-demethylpsoromic acid. Selected specimens examined: Australia: New South Wales: Bains Gully, 3 km S of "Majors Creek, 35°35'S, 149°44'E, 780 m, 1983, H. Streimann 27643 (CBG); Blue Mtns, 4 km SE of Blackheath, walking track from Neates Glen via Grand Canyon to Evans Lookout, 900-1000 m, 1985,

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H. Mayrhofer [6720] & A. Archer (GZU); Mtn. Boss State Forest, Forbes River, 53 km NW of Wauchope, 31°06'S, 152°20'E, 1110 m, 1978, D. Verdon 4030 (CBG); Mt. Kaputar National Park, 'The Gins', 30°06'S, 150°04'E, 1100 m, 1986, P. Merrotsy 242 (BRI-491486); Katoomba, between Leura Falls and Giant Stairways, 33°43'S, 150°19'E, 850 m, 1988, K. & A. Kalb (hb. Kalb 21875); Kurrawonga Falls, 30o21'S, 150°10'30"E, 600 m, 1986, P. Merrotsy 300 (BRI-491491); Morton National Park, 7 km NE of Neriga, 35°38'S, 149°31'E, 760 m, 1981, V. Wirth [10650], J. A. Elix & H. Streimann (STU); Mystery Bay, 12 km S of Narooma, 1977, J. A. Elix 2936 (CBG); Peakhurst near Sydney, 1900 (BRI-475702); Royal National Park, S of Sydney, Bola Creek, E of Waterfall, 34°08'S, 151°02'E, 250 m, 1988, K. & A. Kalb (hb. Kalb 20570); Teudts Hill, 5 km SW of Bundanoon, 680 m, 1980, J. A. Elix 8973 (CBG); Tilba Tilba, 13 km SSW of Narooma, 36°20'S, 150°04'E, 100 m, 1987, J. A. Elix 21615 (CBG); Wollombi Falls, c. 26 mi E of Armidale on Grafton Road, 1967, W. A. Weber & D. McVean (L-49028) (CBG).

Lecanora pseudogangaleoides subsp. verdonii Lumbsch subsp. nov. Subspecies cum thallo ut in Lecanora pseudogangaleoides subsp. pseudogangaleoides, sed ab hac

subspecie arthothelinum et alia xanthona continente differt. Typus: Australia, New South Wales, S. Tablelands, Wadbilliga River Gorge, 41 km ESE of Cooma, 36°18'S, 149°37'E, 650 m, 13 July 1976, D. Verdon 2489 (CBG—holotype).

Etymology: This subspecies is named in honour of the Australian lichenologist and collector of the type material, Mr Doug Verdon (Canberra), who has contributed much to our knowledge of Australian lichens. Chemistry: K+yellow, KC+yellow, C + red, PD+yellow. Major substances: arthothelin, atranorin, psoromic and usnic acids. Minor substances: chloroatranorin, 2,4-dichloronorlichexanthone, 2,5-dichloronorlichexanthone and 2'-O-demethylpsoromic acid. Trace: 4,5-dichloronorlichexanthone. Selected specimens examined: Australia: New South Wales: Blue Mtns, 4 km SE of Blackheath,

walking track from Neates Glen via Grand Canyon to Evans Lookout, 900-1000 m, 1985, H. Mayrhofer [6698] & A. Archer (GZU); Springwood, c. 80 km W of Sydney, Martins Lookout to Glenbrook Creek, 1981, H. Mayrhofer 3407 (hb. Mayrhofer).

Key to the subspecies of L. pseudogangaleoides

and similar species

1

Epihymenium reddish brown to red-brown, with or without crystals, not turning greenish in K; thallus lacking gangaleoidin or psoromic acid 2 Epihymenium olivaceous brown, without crystals, turning greenish in K, thallus containing the gangaleodin or psoromic acid chemosyndrome in addition to usnic acid and/or the atranorin chemosyndrome 3

2(1)

Epihymenium with crystals; thallus containing pannarin, xanthones and the atranorin chemosyndrome, lacking usnic acid L. margarodes Epihymenium without crystals; thallus containing usnic acid and the atranorin chemosyndrome L. wilsonii

3(1)

Usnic acid present, psoromic acid present Usnic acid absent, gangaleoidin present

4 L. gangaleoides

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Thallus C +orange (with the arthothelin chemosyndrome) L. pseudogangaleoides subsp. verdonii Thallus C - (lacking xanthones) L. pseudogangaleoides subsp. pseudogangaleoides Conclusions

As currently understood, the large and diverse genus Lecanora clearly does not represent a natural group. Several entities exist within the genus, but the problem is the circumscription of monophyletic groups within the group. It is tempting to employ chemistry in this matter. Although in some foliose genera the presence of either atranorin or usnic acid provides a simple dichotomy, that correlates with anatomical characters, the situation is far more complex in Lecanora s.str. (Poelt & Leuckert 1993). As already stated by Brodo & Elix (1993) there is no clear boundary between species containing atranorin and those with usnic acid. Given the relative frequency of species with both usnic acid and atranorin (besides the two species mentioned here and L. jamesii and the undescribed species mentioned by Brodo & Elix (1993), there are several additional corticolous taxa, e.g. L. achroa Nyl., L. elatinoides Rasanen, L. queenslandica Knight, L. subflavicans Nyl.) this phenomenon cannot be regarded as extraordinary. Psoromic acid is a P-orcinol depsidone commonly occurring in different groups of lichenized fungi (Culberson 1969, 1970; Culberson et al. 1977). Within the genus Lecanora the substance occurs frequently in the Placodium group, whereas it is scattered in Lecanora s.str. It occurs in species such as L. brunneri Imsh. & Brodo, L. cateilea (Ach.) Massal., L. intumescens

(Rebent.) Rabenh., and L. nemoralis Makarevich (Imshaug & Brodo 1966), as well as L. subcarpinea Szatala (? = L. nemoralis) (Brodo, unpublished), all which have pruinose apothecial discs and are considered to be closely related to L. albella (Pers.) Ach. ( = L. pallida [Schreb.] Rabenh. non Chevall., fide Santesson 1993). Lecanora pseudogangaleoides has epruinose apothecial discs and also differs in possessing an amphithecial cortex and in containing usnic acid. It therefore seems to be related, not to the L. albella group, but to the L. subfusca group, when based on anatomical and morphological characters. The presence of usnic acid cannot be used as a systematic marker in this genus. Taxa containing usnic acid may well belong to Lecanora s.str. (i.e., the L. subfusca group). Further studies are in progress to establish the circumscription of Lecanora s.str. with regard to species lacking atranorin and those containing atranorin and possessing a dark hypothecium. I wish to thank Prof. Dr G. B. Feige (Essen) and Dr I. M. Brodo (Ottawa) for their comments on the manuscript. This study was supported by the Deutsche Forschungsgemeinschaft (Fe 89/6-1). REFERENCES

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