Graphis suzanae Koch & Feuerstein, 2016

Feuerstein, Shirley Cunha, Koch, Natália Mossmann, Lucheta, Fabiane, Vargas, Vera Maria Ferrão & Silveira, Rosa Mara Borges Da, 2016, A new species of Graphis (Graphidaceae: Lichenized Ascomycota) and a revised key of the genus in Rio Grande do Sul, southern Brazil, Phytotaxa 289 (3), pp. 271-278 : 274-275

Graphis suzanae Koch & Feuerstein sp. nov. ( Fig. 2 and 3 )

MycoBank No.: MB 818679

Lirellae with entire labia, disc partially exposed with orange pigment, lateral thalline margin, excipulum laterally carbonized, hymenium clear, ascospores transversely septate, 40–44 μm long.

Type: BRAZIL. RIO GRANDE DO SUL: Maquiné, Forqueta locality ; 308 m elev., 29º32’43.72”S, 50º11’54.77”W; on tree bark in secondary forest patch of Atlantic Forest in initial successional stage; 26 July 2011, NMKOCH 550 ( HAS 90994 , holotype) .

Thallus crustose, continuous, soredia and isidia absent; surface grayish white, opaque, smooth to irregular; cortex present. Lirellae elongated, isolated, a little sinuous, simple to rarely branched, ends acute to rounded, erumpent to prominent, 0.4–1.9 mm long and 0.1–0.2 mm wide, black; disc partially exposed with orange pigment; lateral thalline margin; labia entire, convergent; excipulum laterally carbonized. Hymenium clear, 90–110 μm high, 100–110 μm wide, I–; epithecium orange, 15–23 μm; hypothecium hyaline, 20–25 μm; paraphyses simple, filiform, 1.0–1.5 μm thickness, hyaline with apex orange; periphysoids absent; ascospores hyaline, transversely septate, 7–9-locular, ellipsoid, I+ violet-blue, 40–44 × 8–10 μm, 8/ascus.

Chemistry. Thallus without lichen substances; epithecium pigment orange, K+ purple; TLC: tetra-hydroxyanthraquinone-1, 3, 6, 8 ( Mathey 1987).

Etymology. We dedicate this species to our professor and friend Dr. Suzana de Azevedo Martins, for her contributions to the knowledge of Brazilian lichens and for promoting several lichen studies in southern Brazil.

Discussion. Only four Graphis species with orange, K+ purple pigmentation restricted to the epithecium and/or hymenium are known: Graphis chromothecia R. C. Harris , G. inversa R. C. Harris , G. hodgesiana Lendemer and G. tamiamiensis Lendemer. Of these, G. chromothecia differs by the completely carbonized excipulum, inspersed hymenium and the production of norstictic acid (Lücking 2009; Lendemer 2010). The other species, which share with G. suzanae the laterally carbonized excipulum and the clear hymenium, differ by the production of norstictic acid and by their ascospores characteristics. Graphis hodgesina has muriform ascospores which are much larger than those of G. suzanae (50–100 × 20–30 μm), G. tamiamiensis has smaller, submuriform ascospores not exceeding 35 μm in length, and G. inversa has even smaller ascospores (23–30 μm) and lacks a thalline margin ( Lücking et al. 2009; Lendemer 2010).

Characteristics as the laterally carbonized excipulum, clear hymenium, ascospores transversely septate (between 30–40 μm long) and concealed disc without pruina, are also found in Graphis immersella and G. pinicola . Although morphologically and anatomically similar, they can be easily distinguished: G. immersella has immersed lirellae and produces stictic acid as secondary compound, and G. pinicola does not produce any compounds ( Lücking et al. 2009).

So far, G. suzanae has been found only in two localities (Maquiné and Caraá), where it grows on bark in Atlantic Forest fragments in early stages of succession.

Specimens examined. BRAZIL. RIO GRANDE DO SUL: Caraá ; 77 m elev., 29˚47’03.83”S, 50˚25’38.20”W; secondary forest patch of Atlantic Forest and Semideciduous Forest , 15 November 2014, NMKOCH 551 ( HAS 90995 ) .

Figures

FIGURE 3. Graphis suzanae, holotype: clear hymenium and the pigmented epithecium. Scale = 0.05 mm.