Lobothallia polypycnidiata Lun Wang & Y. Y. Zhang, 2025

Wang, Lun, Feng, Yi-Shan, Wang, Li-Song, Wang, Xin-Yu & Zhang, Yan-Yun, 2025, An overview of the genus Lobothallia (lichenized Ascomycota, Megasporaceae) in China, MycoKeys 125, pp. 205-244 : 205-244

Lobothallia polypycnidiata Lun Wang & Y. Y. Zhang sp. nov.

Fig. 4

Etymology.

The epithet refers to the numerous pycnidia per areole of this species.

Diagnosis.

Thallus areolate, with radiate marginal lobes, pycnidia prominent, usually numerous pycnidia per areole, curved and elongate. This species colonizes diverse substrates, predominantly calcareous and siliceous rocks, with an occasional occurrence on a coniferous stump.

Holotype.

China • Qinghai Prov.: Qumalai Co., Qumahe Vil. , 34°54'53.01"N, 94°46'17.29"E, alt. 4412 m, on rock, 17 September 2020, Xin-Yu Wang et al. XY 20-3034 ( KUN-L 79390 ) .

Description.

Thallus adnate to the substratum, up to 5–7 cm across, centrally areolate, 2–4 mm thick, marginally lobate, 0.5–1 mm thick. Areoles (0.5 –) 0.7–1 (– 1.5) mm wide, angular to rounded, slightly constricted at base, interspaces between areoles (0.05 –) 0.1–0.2 (– 0.4) mm wide, surface flat to slightly convex, grayish-brown covered with white pruina. Lobes simple to irregularly branched, radiate, not overlapping, (1 –) 2–4 (– 5) mm long, (0.6 –) 1–1.5 mm wide, surface pale brown with thin pruina. Upper cortex paraplectenchymatous, 30–50 μm thick, with brown granules (soluble in K); epinecral layer 10–20 µm thick, gelatinous with dark granules (insoluble in K). Algal layer (75 –) 100–150 (– 250) μm thick, discontinuous; photobiont chlorococcoid, cells 8–16 μm diam. Medulla 0.5–1 mm thick, opaque, filled with gray-black granules (insoluble or partially soluble in K). Lower cortex absent.

Apothecia lecanorine, numerous, 1–3 per areole, (0.3 –) 0.8–2 (– 2.5) mm in diameter, clustered or scattered, orbicular to angular by pressure, not to slightly constricted at base; disc plane to slightly concave, black or brown, epruinose (rarely with thin pruina); apothecial margin entire, concolorous with thallus, slightly elevated, persistent but narrowing with disc expansion, 0.15–0.25 mm wide. Exciple narrow, 40–50 μm in the uppermost part. Epithecium, hymenium and subhymenial layers combined 125–150 µm high; epithecium 10–15 µm high; epihymenium 15–25 μm high, with brown (soluble in K) and pale brown (insoluble in K) granules, N-; hymenium 70–100 µm high, hyaline, I + blue; subhymenial layers 40–80 μm high, hyaline, I + blue, hypothecium 30–40 μm, algal layer discontinuous below hypothecium; paraphyses simple, septate, submoniliform to moniliform at the tips, with 2–5 uppermost cells shorter and wider than the basal cells, 4–6 μm wide (basal cells ca. 2 μm wide); asci clavate, Aspicilia - type, hyaline, 8 - spored, 60–70 × 20–30 µm; ascospores simple, hyaline, broadly ellipsoid to ellipsoid, (10.0 -) 11.2–12.0 – 12.8 (- 13.0) × (7.0 -) 7.0–7.8 – 8.5 (- 9.0) µm (n = 38), l / w ratio (1.1 -) 1.4–1.6 – 1.8 (- 1.9), wall ca. 1 µm thick. Pycnidia numerous, usually numerous pycnidia per areole, immersed, unilocular to multilocular, spot-like, 0.1–0.3 mm when young, shortly elongate to curved, 0.4–0.5 × 0.2–0.3 mm at maturity; ostioles dark brown to blackish; conidia bacilliform, hyaline, 5–6 (– 7) × 1 µm.

Chemistry.

Cortex K + yellow to orange-red, P –; medulla K + yellow or orange-yellow, P – or P + pale yellow (near the algal layer), C –, KC –; containing norstictic and connorstictic acids.

Habitat and distribution.

Saxicolous, occasionally growing on the coniferous stump. This species is distributed in Qinghai, Sichuan, and Xizang Prov., China.

Notes.

Lobothallia hedinii is morphologically similar to L. polypycnidiata in general thallus appearance. However, the former differs in its gray to brownish red thallus, parallel lobes of consistent width, and its relatively sparse pycnidia. Chemically, although both species contain norstictic and connorstictic acids, they are distinguished by their medullary spot-test reactions: L. polypycnidiata exhibits P – or P + pale yellow (only near the algal layer), whereas L. hedinii shows a distinct P + yellow reaction. Furthermore, the species differ in reproductive development: L. polypycnidiata specimens consistently show scarce ascus maturation despite the apothecial density, while producing abundant pycnidia; in contrast, L. hedinii displays significantly higher ascus production but fewer pycnidia. Additionally, Lobothallia praeradiosa could be confused with L. polypycnidiata , but differs in its smoother upper surface, loosely adnate lobes with partially overlapping margins, orange-brown apothecial margin, and punctiform pycnidia ( Kou et al. 2013; Paukov et al. 2019).

Additional specimens examined.

China • Qinghai Prov.: Yushu Tibetan Autonomous Prefecture, Qumalai Co., Qumalai Vil. , 34°54'53.01"N, 94°46'17.29"E, alt. 4412 m, on rock, 17 September 2020, Xin-Yu Wang et al. XY 20-753 ( KUN-L 78517 ), Li-Song Wang et al. 20-68344 ( KUN-L 76525 ), 20-67160 ( KUN-L 75336 ) • Zhiduo Co., Zhiqu Vil. , 34°00'44.49"N, 95°47'45.85"E, alt. 4171 m, on rock, 18 September 2020, Li-Song Wang et al. 20-68419 ( KUN-L 76601 ), 20-68413 ( KUN-L 76595 ), Xin-Yu Wang et al. XY 20-808 ( KUN-L 78572 ) • Zaduo Co., Angsai Vil. , 32°50'52.90"N, 95°28'23.05"E, alt. 4051 m, on rock, 17 September 2020, Li-Song Wang et al. 20-67303 ( KUN-L 75480 ), 20-67265 ( KUN-L 75442 ) • Zhaqing Vil. , 32°57'03.90"N, 95°05'29.65"E, alt. 4166 m, on rock, 18 September 2020, Li-Song Wang et al. 20-68582 ( KUN-L 76764 ), 20-68583 ( KUN-L 76765 ) • Ado Vil. , 32°50'52.95"N, 95°28'24.98"E, alt. 4029 m, on dead coniferous wood, 20 September 2020, Li-Song Wang et al. 20-68672 ( KUN-L 76855 ) • Haixi Mongol and Tibetan Autonomous Prefecture, Golmud Ci. , 35°04'24.13"N, 94°07'46.04"E, alt. 4419 m, on rock, 17 September 2020, Li-Song Wang et al. 20-67134 ( KUN-L 75310 ) • Sichuan Prov.: Garze Tibetan Autonomous Prefecture, Shiqu Co., Sexu Town , 33°07'53.16"N, 97°41'46.91"E, alt. 4214, on rock, 21 September 2020, Li-Song Wang et al. 20-68728 ( KUN-L 76911 ) • Xizang Prov.: Langkazi Co., entrance to Karola Glacier , 28°53'54.24"N, 90°13'31.31"E, alt. 4758, on rock, 24 July 2019, Xin-Yu Wang et al. XY 19-2271 ( KUN-L 73043 ) • Chamdo Ci., Jiangda Co., Tongpu Vil. , 31°38'30.46"N, 98°26'11.62"E, alt. 3948 m, on limestone, 23 September 2020, Li-Song Wang et al. 20-68878 ( KUN-L 77062 ), 20-68840 ( KUN-L 77024 ) .

Figures

Figure 4. Lobothallia polypycnidiata. A – L. XY 20-3034 (KUN-L 79390, holotype): A. Thallus; B. Lobes; C. Apothecia; D. Curved pycnidia; E. Vertical section of thallus and pycnidia; F. Densely growing pycnidia; G, H. Section of thallus (H in K reagent); I. Vertical section of apothecium; J. Ascus and ascospores; K. Paraphyses (LCB); L. Conidia. M – N. Other specimens: M. 20-68583, on calciferous rock; N. 20-68878, on calciferous rock; O. 20-68672, on organic substrate. Scale bars: 2 mm (A, N); 1 mm (B, M, O); 0.25 mm (C, D, F); 100 µm (E, G, H, I); 10 µm (J); 5 µm (K, L).