New Record of the Existence of Sarcographa tricosa (Lichenized Ascomycota, Graphidaceace) in Korea.

Lichen genus Sarcographa Fee, a stromatoid Graphidacean taxa, was newly found in Geomun Island, Jeonnam province. The lichen grew on the bark of Camellia japonica and Eurya emarginata along the coastal line of the island. It was identified as Sarcographa tricosa (Ach.) Müll. Arg. for the first time in Korea.

The Graphidaceae are commonly understood to consist of eight genera. Because there has been no phylogenetic approach to delimit the genera in this group, these genera are conveniently, if artificially, defined on the basis of spore morphology and the development of stromatic tissue (differentiated, loosely woven tissue within which ascomata are immersed). A genus has been erected for each combination of hyaline or brown, transversely-septate or muriform-spored, non-stromatic groups (Graphis, Phaeographis, Graphina, Phaeographina) and stromatic groups (Glyphis, Sarcographa, Meduselina, Sarcographina).

There has been no critical appraisal of the family Graphidaceae in Korea. The only information available is "A Checklist of Korean Lichens" that was reported by Hur et al. (2005). In this study, the authors reported the presence of only one genus Graphis from this country. Up to now, 9 species of Graphis have been reported in Korea. In 2009, there was the opportunity for us to study Graphidaceaen lichens of South Korea, and in these studies we identified the presence of another lichen genus Sarcographa (S. tricosa) belonging to this family, which was new to South Korea. A detailed description of S. tricosa along with line diagrams, habitat, ecology and remarks was provided based on the Korean specimen.

The present study is based on lichen specimens housed at the herbarium in the Lichen & Allied Bioresource Center, Korean Lichen Research Insitute (KoLRI), Sunchon National University, Korea. The morphological characters were examined on dry material under a dissecting microscope (× 40). Thallus and ascomata were examined with a compound microscope (× 1000, in oil immersion). The sections for anatomical analysis were mounted in water. All measurements were made in water, but the paraphyses were studied after replacing water with 25% KOH (Wetmore, 1994). The chemicals used during identification were 10% KOH (K), calcium hypochlorite (C), para-phenylenediamine (P), concentrated nitric acid (N) and Lugol's iodine (I). Secondary metabolites were identified by TLC as described by Walker and James (1980). The chromatograms were developed in solvent systems A (toluene: 1, 4-dioxane: acetic acid) and B (hexane: di-ethyl ether: formic acid). Terminology for tissues generally follows that of Staiger (2002).

Sarcographa tricosa (Ach.) Müll. Arg

J. - Mém. Soc. Phys. et Hist. Nat. Genve 29(8): 63 (1887).

≡ Graphis tricosa Ach.; Lichenographia universalis: 674 (1810).

= Sarcographa cascarillae Fée; Essai sur les cryptogams des écorces exotiques officinales: 58 (1825).

Description

Thallus epiphloeodal, thin, effuse, smooth, glossy to matt, yellowish to greenish-grey or greyish-brown, ecorticate; medulla containing many oxalate crystals (Fig. 1B, C & D). Stroma whitish to cream coloured, farinose to granular, roundish to elliptical, often confluent, up to 3 mm in diameter, 0.2~0.3 mm thick, bordered by a white prothallus. Apothecia (lirellae) black, slightly immersed in the stroma, irregularly branched or radiate, forming a network, branches 0.15 mm wide, the ends of branches somewhat acute; disc concave; exciple black, closed, divergent; hypothecium carbonised; hymenium 40~85 µm high, inspersed with oil globules; ascospores 8 per ascus, pale brown to brown, transversely 3 septate, 4-locular, 15~25 × 5~7 µm, old spores with a darker membrane.

Fig. 1

A, Distribution map of Sarcographa tricosa; B, Habitus of (Scale bar = 1 mm) on the bark of Camellia japonica (Hur 070132); C, Ascospores of S. tricosa (not according to scale); D, Vertical and longitudinal section of an apothecium (not according to scale).

Chemistry

Spores I+ brownish-red. TLC: No chemicals.

Ecology and distribution

The species growing on the bark of Camellia japonica and Eurya emarginata along the coastal line of Geomun Island is a new record for Korean lichen flora (Fig. 1A). This is the first time that this genus was reported to exist in South Korea. Outside South Korea, this species has been found in Japan (Nakanishi, 1966), Sri Lanka (Awasthi, 1991; Nakanishi, 1966) and South America (Staiger, 2002).

Remarks

The species is characterised by a whitish stroma that is surrounded by a whitish prothallus and pale brown 4-locular spores. It is often confused with S. medusulina (Nyl.) Müll. Arg. in external morphology, but the latter differs in having 4~6 locular spores and carbonisation of the exciple, which spreads to the adjacent parts of the stroma. While S. tricosa strictly has 4-locular spores and only the exciples of the lirellae are carbonised; adjacent parts of the stroma are not carbonised.

Specimens examined

South Korea, Geomun Island, Yeosu, Jeonnam Prov., N34°00'35.5" E127°19'12.1", alt. 52 m, on bark (Camellia japonica), Hur 070136, 24.03.2007; on bark (Eurya emarginata), Hur 070137; on bark, Hur 070139; Geomun Island, N34°00'35.9" E127°19'12.2", alt. 46 m, on bark, 24.03.2007, Hur 070132.