Chiodecton norsticticum 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 : 282-283

Chiodecton norsticticum Jagadeesh , sp. nov. ( Figs 1A–B & 2E )

MycoBank No.: MB 815257

Chiodecton with perithecioid, solitary to united lirelliform, 150–250 × 100–200 μm ascomata; white pruinose, 0.7–2(–2.5) × 0.5–1.2 mm stroma-like structures; brown to dark brown hypothecium; obovate-oblong, 7-septate, (20–)22–30 × 3–5 μm ascospores, and roccellic and norstictic acids as lichen substances.

Type: — INDIA. Nicobar Islands, Car Nicobar Island, Passa Beach, 9°12’85·1” N, 92°45’90·1” E, alt. 5 m, on coconut palm, 21 Sep. 2014, T. A. M. Jagadeesh Ram 3857 (Holotype CAL, Isotype PBL).

Thallus corticolous, epiphloeodal, up to 10.5 cm in diam., tightly attached, ± byssoid, minutely felty, smooth, becoming verrucose, rimose, whitish grey to greyish yellow, greyish, epruinose, ecorticate to corticate, 80–170 μm thick, with few to many up to 15 μm wide calcium oxalate crystals; prothallus indistinct, forming a black line while bordering same or different species; cortex 12–35 μm thick; photobiont layer 15–45 μm thick; photobiont Trentepohlia , cells single or few cells aggregated, 9–18 × 6–10 μm; medulla whitish, 30–95 μm thick. Ascomata perithecioid, solitary to united lirelliform, and aggregated in slightly elevated stroma-like structures, 150–250 × 100–200 μm; stroma-like structures white pruinose, usually with more than 10 ascomata per stroma, 0.7–2(–2.5) × 0.5–1.2 mm, up to 0.4 mm high, ± constricted at base, lacking yellow pigment below the ascomata, with patches of calcium oxalate crystals. Excipulum brown to dark brown, 5–20 μm thick. Hymenium colourless, 60–115 μm high, not inspersed with oil droplets and granules, I + blue quickly turns red except the uppermost 12–30 μm which is partly I + blue, KI+ blue. Hypothecium extending down to the substrate, 12–80 μm thick, upper part thin, dark brown and hard, lower part soft and pale brown. Paraphysoids branched and anastomosing, 1 μm wide; tips slightly thickened, 1–2 μm wide. Asci clavate, 8-spored, 45–60 × 10–12 μm. Ascospores colourless, obovate-oblong, 7-septate, (20–)22–30 × 3–5 μm. Pycnidia few to many, solitary, scattered to aggregated along borders (prothallus), slightly elevated, globose to subglobose, black, up to 0.15 mm diam. Conidia colourless, filiform, straight to slightly curved, 4–5(–6) × 1 μm. Chemistry: Thallus K + yellow turns red, C –, P + yellow, UV + grey white; I –, KI– (in section); roccellic acid (major) and norstictic acid (major).

Notes: — Chiodecton norsticticum is distinct in having small 7-septate ascospores, and norstictic and roccellic acids as lichen substances. Chiodecton andamanicum Jagadeesh , C. mucorinum Zahlbr. and C. natalense Nyl. are the other species having more than 3-septate ascospores. Chiodecton andamanicum Jagadeesh differs in 4–5-septate ascospores and lacking norstictic acid. Chiodecton mucorinum Zahlbr. and C. natalense Nyl. also lack norstictic acid but have rather large (over 35 μm long) ascospores ( Jagadeesh Ram 2014, Thor 1990).

Distribution and habitat: — Chiodecton norsticticum has found to be common on Car Nicobar Island of the Nicobar Islands, where it grows on the trunks of over 50 year old coconut palms.

Etymology: —The specific epithet refers to its secondary metabolite, norstictic acid.

Additional specimens examined: — INDIA. Nicobar Islands , Car Nicobar Island: Tapoiming village, 9°12’94·8” N, 92°47’94·2” E, alt. 8 m, on coconut palm, 21 Sep. 2014, Jagadeesh Ram 3962 ( PBL) ; ibid., Kimius village , 9°07’74·0” N, 92°45’70·7” E, alt. 5 m, on coconut palm, 22 Sep. 2014, Jagadeesh Ram 4032 ( PBL) ; Tamaloo village , 9°11’23·9” N, 92°49’30·0” E, alt. 6 m, on coconut palm, 23 Sep. 2014, Jagadeesh Ram 4110 ( PBL) ; ibid., 9°11’03·6” N, 92°48’75·7” E, alt. 6 m, on coconut palm, 23 Sep. 2014, Jagadeesh Ram 4114 ( PBL) .

Figures

FIGURE 1. A–B. Chiodecton norsticticum (holotype), part of thallus with perithecioid to lirelliform ascomata in stroma-like structures. C–D. Enterographa nicobarica (holotype), part of thallus with lirelliform ascomata in pseudostroma-like structures. Scales:A–D=1 mm.

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.