Coenogonium coronatum Neuwirth & Stocker-Wörgötter, Bryologist

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 : 109-110

Coenogonium coronatum Neuwirth & Stocker-Wörgötter, Bryologist 117 (2): 163 (2014). ( Fig. 6B )

Thallus crustose, usually foliicolous or rarely corticolous, continuous, thin, smooth, yellowish green to vivid green, 5– 30 mm diam., without a distinct corticiform layer; prothallus absent. Photobiont Trentepohlia , cells angular to rounded, mostly in irregular plates, partly short threads, cells 10–20 × 5–7 μm. Apothecia epiphyllous, sessile, rounded in outline, 0.1–0.5 mm diam. and 120–155 μm high; disc plane, concave in young apothecia, pale yellow to creamy; margin thin, prominent, densely pilose, cream-colored; hairs consisting of fungal hyphae, 5–30 long, sometimes abraded in older apothecia. Excipulum paraplectenchymatous with irregularly arranged cells, 45–70 μm broad, outer part I+ yellow-brown, inner part I–; cells globose to elongate, thin- or partly thick-walled, 1–10 × 2–5 μm. Hypothecium 15–30 μm high, colorless to pale yellowish. Hymenium 45–60 μm high, colorless, I+ brown. Asci 40–50 × 5 (if spores oblique-uniseriate) –10 μm (if spores irregularly biseriate). Ascospores oblique-uniseriate or irregularly biseriate, broadly ellipsoid, 1-septate, 8–12 × 3–3.5 μm, 2.2–3 times as long as broad. Pycnidia not observed but when present, wart-shaped, 0.12–0.15 mm diam., white with beaks. Conidia ellipsoid, non-septate 2–5 × 1–2 μm (fide Neuwirth et al. 2014). Chemistry: no substances detected by TLC.

Distribution and habitat:—Our collections indicate that the species is widespread and at least locally abundant and with a wide ecological amplitude in SE Asia on bark and leaves of various trees and bushes in the understory of tropical rainforests, mixed deciduous forests and dry evergreen forests from 15–1055 m.

Remarks:—The records from Borneo extend the known distribution range to the south east. The species is very similar to C. subluteum (Rehm) Kalb & Lücking , the most abundant and widespread species, but differs in having cilia on the outer excipulum. This species often grows together with C. coronatum on the same leaf. The arrangement of the ascospores within the asci varies considerably. In some asci, the spores are arranged oblique-uniseriate while in others of the same apothecium, they are arranged irregularly biseriate. Sometimes, the uppermost four spores in an ascus are arranged biseriate and the lowest four spores are arranged uniseriate. C. barbatellum Kalb from Australia is also very similar. Aside from growing on bark, it differs in having smaller ascospores (7–8 × 2–3 μm) and an orange rather than a pale yellow or creamy disc.

Material examined:— THAILAND. Saraburi Province: Muaklek district ; Khao Yai National Park, along trail from Heo Pla Kang waterfall ( Khao Fa Pha ) to Khao Nom Nang and Sun Sup Tai , epiphyllous in a dry evergreen forest, 1055 m, 14°31’03.30’’ N, 101°16’40.40’’ E, 27 June 2000, K. Papong RU-20479, RU-20483 ( RAMK 00169 , 009171 ) ; ibid. 28 June 2000, K. Papong RU-20500. RU-20555 ( RAMK 009194 , 009190 ) ; Nakhon Ratchasima Province: Khao Yai National Park, along trail from visitor center to Gibbon’s camp, epiphyllous in a tropical rainforest, 875 m, 14°26’26.19’’ N, 101°21’57.80’’ E, 20 June 2000, K. Papong RU-20476-2 ( RAMK 009165 ) ; Prachuap Khiri Khan Province: Bang Saphan district ; Tambon Mae Rumphueng, Pa Klang Ao Forest Park, along road #4045, in a secondary dry evergreen forest with Dipterocarpus alatus , on leaves of various bushes, 15 m. 11°12‘36.6‘‘ N, 99°31‘25.7‘‘ E, 20 December 2015, J. Sutjaritturakan & K. Kalb 41458, (herb. K. & J. Kalb) ; Chumphon Province: Lamae district ; ascent from Khao Set village to Khao Set mountain , in a mixed deciduous forests, 30 m, 09°47’ N, 99°06’ E, 3 April 2012, K. Kalb (39803), V. Poengsungnoen & M. Sodamuk, (herb. K. Kalb 39803) ; MALAYSIA. Borneo : Sarawak ; Kuching, Bako National Park ( Lintang trail), ca. 25 km NNE of Kuching ; in a coastal tropical rainforest, 50 m, 01°42’36’’ N, 110°26’39’’ E, 16 August 2014, K. Kalb (41138, 41449) & A. Mertens ; Sabah; Kota Kinabalu, Sapi Island ( Pulau Sapi ), in a coastal tropical rainforest, 30 m, 06°00’17’’ N, 116°00’57’’ E, 8 August 2014, K. Kalb (41136) & A. Mertens (herb. K. Kalb 41136) .

Coenogonium dilucidum (Kremp.) Kalb & Lücking, In : Lücking & Kalb, Bot. Jahrb. Syst. 122 (1): 32 (2000). ( Fig. 6C )

Lecidea dilucida Kremp., J. Mus. Godeffroy 1 (4): 103 (1873); Dimerella dilucida (Kremp.) R. Sant., Symb. Bot. Upsal. 12 (1): 394 (1952).

Thallus crustose, foliicolous, rarely corticolous, continuous, thin, smooth, green, greenish grey or brownish grey, dull. Photobiont Trentepohlia , cells angular to rounded, mostly in irregular plates, partly short threads, cells 9–15 × 5–8 μm. Apothecia sessile, rounded, 0.15–0.3 mm diam., 70–100 μm high; disc plane or concave, pale wax-colored; margin comparatively thick, prominent, smooth, of same color as disc. Excipulum 30–40 μm broad, colorless, outer part I+ light brown, inner part I–; cells isodiametric to elongate, ± thick-walled, 4–6 × 2–4 μm. Hypothecium 5–10 μm high, colorless. Hymenium 55–65 μm high, colorless, I+ blue then quickly reddish brown then greyish brown. Asci 35–45 × 7–9 μm. Ascospores oblique-uniseriate or irregularly biseriate, ellipsoid, 1-septate, 6–12 × 2.5–3.5 μm, 2.4–4 times long as broad. Pycnidia rare, wart-shaped, 0.1–0.15 mm diam., pale green. Conidia bacillar, 1-septate, 13–18 × 2–2.5 μm. Chemistry: no substances detected by TLC.

Distribution and habitat:—Pantropical. Typically foliicolous, but well-developed specimens have also been found on bark ( Lücking 2008). In Thailand it was collected in the understory of tropical rain forests, mixed deciduous forests and dry evergreen forests from 185–1055 m.

Remarks:— Coenogonium dilucidum is very closely related to C. subluteum . They are the most common, foliicolous, crustose species of the genus and sometimes are difficult to distinguish. Well developed specimens differ by the size and color of the apothecia, i.e. pale wax-colored and 0.15–0.3 mm diam. in C. dilucidum and more brightly colored apothecia with an orange tinge and 0.2–0.5 mm diam. in C. subluteum . Furthermore, pycnidia are usually abundant in C. subluteum , and give the thallus a verrucose appearance while they are rare or absent in C. dilucidum .

Selected material from Thailand examined:— THAILAND. Saraburi Province: Muaklek district ; Khao Yai National Park, along trail from Heo Pla Kang waterfall ( Khao Fa Pha ) to Khao Nom Nang and Sun Sup Tai, epiphyllous in a dry evergreen forests, 1055 m, 14°31’03.30’’ N, 101°16’40.40’’ E, 27 June 2000, K. Papong RU-20480 ( RAMK 009170 ). Nakhon Ratchasima Province: Pakchong district ; Khao Yai National Park, along trail from visitor center to Gibbon study area, Mo Sing To , epiphyllous in a tropical rainforest, 830 m, 14°25’56.37’’ N, 101°22’14.36’’ E, 15 May 2001, K. Papong RU-21055, RU-21056 ( RAMK 009203 , RAMK 009202 ). Prachinburi Province: Nadi district ; Khao Yai National Park, near the station Bu Phram Nai ( Check Point 6), epiphyllous in a mixed deciduous forests, 185 m, 14°15’56.46’’ N, 101°51’09’’ E, 11 March 2000, K. Papong RU-17537-1, RU-17541, RU-17544, RU-17525-1 ( RAMK 004682 , RAMK 004706 , RAMK 004708 , RAMK 009077 ) .

Figures

FIGURE 6. Habitus photographs of Coenogonium species. A. Coenogonium convexum (KK 41133), scale 1 mm. B. Coenogonium coronatum (KK 41136), scale 0.5 mm, scale of inlet 0.15 mm. C. Coenogonium dilucidum (KJ 41439), scale 0.25 mm. D. Coenogonium epiphyllum (RAMK 009100), scale 0.25 mm. E. Coenogonium frederici (Isotype, KK 41445), scale 0.5 mm. F. Coenogonium geralense (KK 41446), scale 1 mm.