Gyrographa nigrofusca Jagadeesh, 2016

Jagadeesh Ram, T. A. M., 2016, Additional new species in Roccellaceae s. l. from the Andaman and Nicobar Islands, India, Phytotaxa 246 (4), pp. 281-286 : 284-285

Gyrographa nigrofusca Jagadeesh , sp. nov. ( Figs 2A–D & 2G )

MycoBank No.: MB 815259

Gyrographa with endophloeodal inconspicuous thallus, simple to substellate lirelliform ascomata, 7-septate, 27–34 × 3–4.5 μm ascospores and lacking lichen substances.

Type: — INDIA. Andaman Islands, Little Andaman, R. K. Pur, Vishnu Nala Dam forest, 30 m, 4 May 2012, T. A. M. Jagadeesh Ram 1668 (Holotype CAL, Isotype PBL).

Thallus crustose, corticolous, endophloeodal, inconspicuous, irregular, up to 10 cm across, greyish brown to brown, thin, indistinct, ecorticate, 12–35 μm thick; prothallus black; photobiont Trentepohlia , cells 6–12 × 4–8 μm. Ascomata few to numerous, scattered to even, lirelliform, usually simple, furcate, substellate, straight to flexuous, 0.6–2.5(–5) mm long, 0.2–0.35(–0.4) mm wide; disc a narrow slit, epruinose, rarely exposed. Excipulum continuing below the subhymenium, black, carbonized, 36–90 μm thick laterally, 60–150 μm thick at base, K + olive-green. Epihymenium brownish, 11–15 μm thick, K –, I + blue turns red. Hymenium colourless to pale brown, 42–68 μm high, I + blue partly turns red, KI+ blue. Subhymenium pale brown, 8–15 μm thick, blue turns red, KI+ blue. Paraphysoids branched and anastomosing, 1–1.5 μm wide. Asci clavate, 8-spored, 42–62 × 12–17 μm. Ascospores colourless, fusiform, 6–7(–8) septate, 27–34 × 3–4.5 μm; perispore absent. Pycnidia not observed. Chemistry: Thallus K –, C –, KC–, P –, UV –; I –, KI– (in section); no lichen substances.

Notes: —The genus Gyrographa has recently been established to accommodate the Opegrapha species having thickened carbonized hypothecium or basal excipulum and lacking gelatinous perispores (Ertz et al. 2015). Gyrographa nigrofusca is distinguished from the only other corticolous Gyrographa gyrocarpa (Flot.) Ertz & Tehler by the nonsorediate thallus without secondary metabolites and the 7-septate ascospores while the latter has a sorediate thallus with gyrophoric acid and 3-septate ascospores. Opegrapha dekeselii Ertz shows somewhat resemblance with the new species in having 7-septate ascospores and similar hymenial reaction with Iodine which is also common in the Andaman and Nicobar Islands, but Gyrographa nigrofusca is distinct in having thickened excipulum and lacking perispores ( Ertz 2009, Ertz et al. 2015).

Distribution and habitat: — Gyrographa nigrofusca was found on coastal to inland evergreen rainforests in the Andaman Islands.

Etymology: —The specific epithet refers to its brown thallus and black ascomata.

Additional specimens examined: — INDIA. Andaman Islands : North Andaman : Coffee Dera, Lamba Baalu, alt. 5 m, 20 Mar. 2012, Jagadeesh Ram 1329 ( PBL) ; ibid., Paget Island Wildlife Sanctuary , 10 m, 21 Mar. 2012, Jagadeesh Ram 1364 ( PBL). Little Andaman: Hut Bay, Evergreen forest along White Surf waterfall, alt. 30 m, 2 May 2012, Jagadeesh Ram 1555, 1575 ( PBL) ; ibid., R. K. Pur , Vishnu Nala Dam forest, 30 m, 4 May 2012, Jagadeesh Ram 1688 ( PBL) .

Figures

FIGURE 2. A–B. Gyrographa nigrofusca (holotype), part of thallus with lirelliform ascomata. C–D. G. nigrofusca (Jagadeesh Ram 1688), part of thallus with lirelliform ascomata. E. Chiodecton norsticticum (holotype), ascospores. F. Enterographa nicobarica (holotype), ascospores. G. Gyrographa nigrofusca (holotype), ascospores. Scales: A–D=1 mm, E–G=10 μm.