Graphis subschroederi J. Kalb, Lücking & Kalb, 2018

Kalb, Jutarat, Lücking, Robert & Kalb, Klaus, 2018, The lichen genera Allographa and Graphis (Ascomycota: Ostropales, Graphidaceae) in Thailand-eleven new species, forty-seven new records and a key to all one hundred and fifteen species so far recorded for the country, Phytotaxa 377 (1), pp. 448-450 : 448-450

** Graphis subschroederi J. Kalb, Lücking & Kalb , sp. nov. Fig. 8C .

Mycobank MB 827647

Similar to Graphis schroederi Zahlbr. , but differs in having a brownish thallus (greenish gray in G. schroederi ), smaller ascospores (70–90 × 10–14 μm in G. schroederi ) and in having a laterally carbonized exciple (completely carbonized in G. schroederi ).

Type:— THAILAND. Chumphon province: Lamae district, ascent from Khao Set village to Khao Set mountain , in a mixed deciduous forest, ca. 250 m, 09°48’ N, 99°07’ E, 3 april 2012, K. Kalb 39098, V. Poengsungnoen & M. Sodamuk ( RAMK, holotype, hb. K. Kalb, isotype) .

Etymology:—The specific epithet refers to the great overall similarity with G. schroederi .

Thallus corticolous, brown-gray to olive-gray, up to 9 cm diam., 80–100 μm thick, continuous, corticate, prothallus indistinct, surface smooth to uneven due to clusters of crystals, mostly glossy. Thallus in section with distinct upper cortex, up to 30 μm high, with irregular algal layer up to 40 μm high, medulla and algal layer with clusters of crystals. Lirellae erumpent with thick, apically complete, gently sloping thalline margin, but labia still visible, elongate, up to 4 mm long and 0.2–0.3 mm wide, 0.2 mm high, straight, curved or sinuous, irregularly branched, labia convergent, entire, black, not pruinose, disc closed, not visible from above, (subserpentina- morph). Exciple laterally carbonized, 25–50 μm wide,; hypothecium 10–15 μm high, ± hyaline; hymenium 100–125 μm high, clear, epihymenium indistinct. Paraphyses unbranched; asci elongate claviform, ca. 90–110 × 20–25 μm. Ascospores 8/ascus, hyaline, transversely 14–20 (–25)-septate, 55–75 × 7–9 μm, with a halo up to 3 μm thick, I+ blue.

Chemistry: stictic acid (major), constictic acid (minor) (anal. K. Kalb).

Distribution and habitat:—The new species is so far only known from the type locality where it is growing abundantly on smooth bark of an unidentified tree, in a mixed deciduous forest at ca. 250 m elevation.

Remarks:—As the spore size in Graphis species, especially in those with medium- to large-sized ascospores can vary considerably, more material from other localities would be desirable. However, we described the new species, because it also has a laterally carbonized exciple, which is completely carbonized in G. schroederi .

Figures

FIGURE 8. A. Graphis sublitoralis (scale = 0.5 mm); B. Graphis submarginata (scale = 0.4 mm); C. Graphis subschroederi (scale = 0.4); D. Graphis sundarbanensis (scale = 0.4); E. Graphis tenuirima (scale = 0.4 mm); F. Graphis urandrae (scale = 0.5 mm).