Coenogonium interplexum Nyl., Ann. Sci. Nat. Bot.

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 : 112

Coenogonium interplexum Nyl., Ann. Sci. Nat. Bot. sér. 4,16: 92 (1862). ( Fig. 7A )

Thallus filamentous, usually corticolous, rarely foliicolous, prostrate and effuse, irregularly interwoven, with large interspaces between individual filaments, yellow-green to brownish green, up to 40 mm wide, ecorticate; prothallus absent. Photobiont Trentepohlia , cells cylindrical, in distinct filaments, 40–60 × 20–25 μm diam.Apothecia substipitate or conical, rounded, 0.25–0.8 mm diam., 150–200 μm high; disc flat, yellow-orange; margin thin, not prominent, smooth, cream-colored. Excipulum paraplectenchymatous with radiating cell rows, 60–100 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 at the periphery, 5–12 × 3–10 μm. Hypothecium 15–25 μm high, colorless. Hymenium 55–70 μm high, colorless, I+ blue then quickly reddish brown then greyish brown. Asci 60–70 × 4–7 μm. Ascospores uniseriate or irregularly biseriate, ellipsoid, 1-septate, 7–10 × 2–3 μm, 2.3–3.6 times as long as broad. Pycnidia globose, cream-colored; conidia non-septate, fusiform-ellipsoid, 5–8 × 1.5–2 μm. Chemistry: no substances detected by TLC.

Distribution and habitat:—Pantropical: North, Central and South America, Thailand, Australia. This species grows on the bark of various trees in tropical rainforests, lower montane forests and dry evergreen forests from 760– 830 m.

Remarks:— C. interplexum is distinguished by the prostrate thallus formed from irregularly woven filaments which is not easily detached from the substrate (mostly bark). C. interpositum Nyl. is very similar and differs mainly by having non-septate ascospores. Here we cite only fertile specimens where spores were observed.

Material from Thailand examined:— Nakhon Ratchasima Province: Pakchong district ; Khao Yai National Park, lower montane forests along main road 3077 at km 2 to Khao Khiao site, 830 m., 14°23’46.61’’ N, 101°22’45.63’’ E, 17 June 1999, R. Noicharoen 14874 ( RAMK 027802 ) ; ibid. tropical rainforest along Pha Klua Mai nature trail to Heo Suwat waterfall, 760 m, 14°26’7.19’’ N, 101°24’25.81’’ E, 14 November 2001, Lai RU-21260 ( RAMK 008212 ) ; ibid. along trail from Mo Sing To to the former restaurant of Tourist Authority of Thailand ( TAT), dry evergreen forests, 830 m, 14°24’3.37’’ N, 101°21’58.14’’ E, 1 June 2000, W. Polyiam 19902 ( RAMK 027811 ) .

Figures

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.