Coenogonium leprieurii (Mont.) Nyl., Ann. Sci. Nat. Bot., Ser.

Kalb, Jutarat, Boonpragob, Kansri & Kalb, Klaus, 2016, New Coenogonium species (Ostropales: Coenogoniaceae) from Thailand, new reports and a revised key to the species occurring in the country, Phytotaxa 283 (2), pp. 101-122 : 114-115

Coenogonium leprieurii (Mont.) Nyl., Ann. Sci. Nat. Bot., Ser. 4, 16: 89 (1862). ( Figs. 5D , 7E )

Coenogonium linkii var. leprieurii Mont., Ann. Sci. Nat. Bot., Ser. 3, 16: 47 (1851).

Thallus filamentous, mostly corticolous, seldom foliicolous on old, perennial leaves, usually forming hemispherical, shelf-like structures projecting horizontally from the substrate, yellow-green to bright green, up to 40 mm across, ecorticate; prothallus absent. Photobiont Trentepohlia , cells cylindrical, in distinct, branched filaments, 12–18 × 5–8 μm diam. Apothecia usually formed on the underside of the thallus, substipitate or conical, rounded, 0.25–0.6 mm diam., 100–150 μm high; disc flat, pale orange to yellow-orange; margin thin, not prominent, smooth, cream-colored. Excipulum paraplectenchymatous with radiating cell rows, 30–50 μm broad, colorless, outer part I+ yellow-brown, inner part I–; cells isodiametric and rather thick-walled in inner parts, 4–8 μm diam., radiately elongate and thin-walled in the periphery, 5–12 × 3–10 μm. Hypothecium 9–12 μm high, colorless. Hymenium 45–60 μm high, colorless, I+ blue then quickly reddish brown then greyish brown. Asci 40–55 × 5–7 μm. Ascospores irregularly biseriate, ellipsoid, non-septate, 5–8 × 2–3 μm, 2.4–3.1 times as long as broad. Pycnidia globose, cream-colored; conidia non-septate, fusiform-ellipsoid, 6–7 × 1.5–2 μm. Chemistry: no substances detected by TLC.

Distribution and habitat:—South and Central America, Thailand. Usually growing on bark of trees in the understory of hill evergreen forests, lower montane forests, tropical rainforests and dry evergreen forests from 825– 1375 m. In the relevant literature (e. g. Rivas Plata et al. 2006, Lücking 2008) the distribution is said to be pantropical, but we have found no reports from Africa or Australia in the literature. C. leprieurii is a new addition to the Thai lichen biota and a new report for SE Asia.

Remarks:— C. leprieurii is distinguished by its filamentous, shelf-shaped thallus which projects from the substrate, apothecia on the underside of the thallus and non-septate ascospores (erroneously reported to be 1-septate in the description by Lücking 2008). It is very similar to C. linkii , but this species has 1-septate ascospores.

Material from Thailand examined:— Nakhon Ratchasima Province: Pakchong district ; Khao Yai National Park, hill evergreen forests E of main road 3077 to Khao Khiao site, 1,375 m., 14°21’36.46’’ N, 101°23’46.83’’ E, 2 September 2005, K. Tengyong RU-22581 (kk5) ( RAMK 008362 ) ; ibid .; hill evergreen forests at Khao Khiao site, 830 m., 14°23’46.61’’ N, 101°22’45.63’’ E, 11 January 2003, K. Noicharoen RU-21591 (kk5) ( RAMK 007203 ) ; ibid., lower montane forests along trail at km-stone 9 of Khao Rom site, near junction to Khao Khiao , 830 m, 14°24’22.33’’ N, 101°22’15.53’’ E, 04 April 1999, W. Khamtim 13467 ( RAMK 027805 ) ; ibid., tropical rainforest at Gibbon Camp behind food center, Khao Yai Head Quarter , 875 m, 14°26’26.19’’ N, 101°21’57.80’’ E, 1 February 2009, M. Sodamuk 13 ( RAMK 027806 ) ; dry evergreen forests along tourist trail to Krong Kaew waterfall, 825 m, 14°26’29.43’’ N, 101°22’30.97’’ E, 05 February 1999, K. Noicharoen 15380 ( RAMK 027804 ) ; ibid., dry evergreen forests at km 33 of nature trail from main road 2090 to Nhong Pak Chee area , 830 m, 14°27’35.11’’N, 101°20’09.51’’ E, J. Sutjaritturakan 12621 ( RAMK 027810 ) .

Figures

FIGURE 5. A. Coenogonium convexum (KK 41133), transverse section through the crustose thallus showing the corticiform layer, scale 15 μm. B. Thallodiscs laying upside down on the thallus of Coenogonium isidiiferum (KK 41459), scale 0.3 mm, scale of inlet 0.1 mm. C. Coenogonium luteum (Schumm 8577), exciple coloured with lactophenol-anilinblue, scale 20 μm. D. Coenogonium leprieurii (RAMK 027804 b), ascus tip stained permanently blue with Lugol‘s solution. E. and F. Coenogonium aff. borinquense (KK 38577) showing different arrangement of ascospores within the asci of the same section, scales 5 μm and 10 μm. G. Coenogonium subborinquense (KK 38820), irregular shaped pycnidia, scale 0.2 mm. H. Coenogonium subluteum (RAMK 004684 b), hymenium stained with Lugol‘s solution; after some time, the upper part still remains blue while the lower part has turned red brown. I. Coenogonium luteum (Schumm 8577), hymenium stained with Lugol‘s solution; after some time, the whole hymenium has turned red brown. J. Conogonium barbatum (RAMK 004687), habitus, filamentous thallus projecting from the margin of a leaf, scale 1.5 mm.

FIGURE 7. Habitus photographs of Coenogonium species.A. Coenogonium interplexum (RAMK 027802), showing a young substipitate apothecium (upper part), scale 0.4 mm. B. Coenogonium isidiatum (KK 24025), scale 2 cm. C. Coenogonium isidiiferum (KK 41459), marginal part of thallus, scale 0.4 mm. D. Coenogonium isidiiferum (KK 41459), exfoliating thallodiscs, leaving ± round holes in the thallus, scale 0.2 mm. E. Coenogonium leprieurii (RAMK 27804), scale 1 mm, scale of inlet 0.5 mm. F. Coenogonium luteum (KK 24052), scale 1 mm.