Malmidea tratiana Kalb & Mongkolsuk, 2012

Kalb, Klaus, Buaruang, Kawinnat, Mongkolsuk, Pachara & Boonpragob, Kansri, 2012, New or otherwise interesting Lichens. VI, including a lichenicolous fungus, Phytotaxa 42, pp. 35-47 : 44

Malmidea tratiana Kalb & Mongkolsuk sp. nov. ( Fig. 2I ) Mycobank MB 564184

Sicut Malmidea furfurosa (Tuck. ex Nyl.) Kalb & Lücking sed thallo leve et sporis minoribus differt.

Type:— THAILAND. Trat Province: Muang District, near Ban Nam Chieo , in a ± disturbed mangrove forest on Rhizophora apiculata , ± 3 m, 12°10’25’’ N, 102°28’37’’ E, 25 February 2011, K. Kalb & P. Mongkolsuk (holotype RAMK, isotype hb. Kalb 38852) .

Etymology:—This species is named after the type locality in Trat Province.

Thallus crustose, corticolous, continuous, 150–250 µm thick, ± smooth or slightly bullate, green to greengrey, phenocortex ca. 10–15 µm thick with small crystals, algal layer 80–100 µm thick, medulla indistinct, ca. 60–150 µm thick, prothallus whitish, soralia and isidia absent. Photobiont chlorococcoid, cells 7–10 µm diam. Apothecia sessile, round, 0.3–0.5 mm diam. and 0.25–0.35 µm high; disc plane to slightly concave, pale leather brown to grey-brown; margin of piperis - type ( Kalb et al. 2011), thick, prominent, black. Thalline exciple absent, proper exciple dark brown internally, outer part ± hyaline, 45–100 µ m wide without hydrophobic granules, KOH-. Hypothecium 70–100 µm high, blackish brown, KOH-. Epihymenium hyaline. Hymenium 70–80 µm high, hyaline. Asci 60–70 × 15–18 µm, 6–8 spored. Ascospores non-septate, wall uniformly thickened, halonate, ellipsoid to fusiform, 9–11 × 5–6 µm, halo 1 µm thick. Pycnidia not observed. Chemistry: an unknown spot with R f values 37, 9, 23 in solvents A, B’, C (Elix & Ernst-Russell 1993).

Notes:— Malmidea species with a piperis - type exciple are rare in the tropics but more abundant in subtropical regions or at higher elevations. On the other hand, species with a granifera - type exciple are more common in the tropics or at lower elevation. Kalb et al. (2011) mention only one species ( Malmidea perplexa Kalb ) with a piperis - type exciple for Thailand. Malmidea tratiana is readily distinguished from that species by its dark brown hypothecium (hyaline in M. perplexa ) and the black margin of the apothecia (whitish grey to dark brownish grey in M. perplexa ). Malmidea tratiana differs from the neotropical M. furfurosa (Tuck. ex Nyl.) Kalb & Lücking by the ± smooth thallus (granular to isidiose in M. furfurosa ) and smaller ascospores (9–11 × 5–6 µm versus 11–14 × 5–7.5 µm). Furthermore, no secondary lichen products could be detected in M. furfurosa by means of TLC.

Figures

FIGURE 2. G. Malmidea incrassata (holotype), thallus with apothecia; Scale: 1.5 mm. H. Malmidea reunionis (holotype), thallus with apothecia; Scale: 2 mm. I. Malmidea tratiana (holotype), thallus with apothecia; Scale: 0.5 mm. J. Melaspilea lekae (holotype), ascocarps on thallus of Sarcographa labyrinthica; Scale 0.5 mm. K–L. Stirtonia rhizophorae (holotype), K. thallus with ascigerous zones; Scale: 1 mm. L. ascospore; Scale: 13 µm.