Leucodermia leucomelos, Mongkolsuk, Pachara, Meesim, Sanya, Poengsungnoen, Vasun, Buaruang, Kawinnat, Schumm, Felix & Kalb, Klaus, 2015

Mongkolsuk, Pachara, Meesim, Sanya, Poengsungnoen, Vasun, Buaruang, Kawinnat, Schumm, Felix & Kalb, Klaus, 2015, The lichen family Physciaceae in Thailand-II. Contributions to the genus Heterodermia sensu lato, Phytotaxa 235 (1), pp. 448-450 : 448-450

3. Leucodermia leucomelos (L.) Kalb, comb. nov. ( Fig. 10B )

Mycobank MB 813827

Basionym: Lichen leucomelos L., Sp. Pl., 2nd edn, 2: 1613 (1763); Parmelia leucomela (L.) Ach., Methodus 256 (1803); Physcia leucomelos (L.) Michx., Fl. Bor.- Amer. 2: 326 (1803); Borrera leucomela (L.) Ach., Lichenogr. Univ. 499 (1810); Anaptychia leucomelaena (L.) A. Massal., Mem. Lichenogr. 35 (1853); Heterodermia leucomelos (L.) Poelt, Nova Hedwigia 9: 31 (1965). Type:—AMERICA MERIDIONALIS [SOUTH AMERICA]; (LINN 1273.109, holotype n.v., fide Jørgensen et al. 1994: 329, 378).

Remarks: — Many synonyms as well as varieties and forms are listed for this species in Kurokawa (1962) and elsewhere. They are not repeated here, because they may well represent independent species when modern chemical and molecular methods are applied to their delimitation.

Thallus foliose to subfruticose, often in loose rosettes or forming tangled mats, loosely adnate or, in part, unattached, 5–15 cm wide. Lobes 0.5–4.0 mm wide, separate, ±plane, linear-elongate, ribbon-like, tangled, dichotomously branched, often ascending at the apices or, occasionally, the apices reflexed, with conspicuous long, gray to black simple or squarrosely branched marginal rhizines, 5–15 mm long. Upper surface ivory to gray-white, smooth, epruinose. Medulla white. Lower surface predominantly ecorticate, but with thickened corticated margins, canaliculate, arachnoid or powdery and then becoming sorediate, often with subapical soralia, white throughout or partially pinkish brown or, rarely, purple; yellow pigments absent. Apothecia rare, subapical to apical, substipitate to distinctly stipitate, 2–5 mm wide; margin crenulate to lobulate, the lobules triangular, to 3 mm long, often with sparse short black cilia along the margins of the lobules; disc concave, dark brown to black, ± white-pruinose. Ascospores Polyblastidia - type, ellipsoidal, with numerous small or large sporoblastidia, 31–50 × 15–24 µm. Pycnidia rare, immersed, visible as black dots; conidia

Chemistry: Cortex K+ yellow, C–, KC–, P+ yellow; medulla K+ yellow then red, C–, P+ dark yellow; containing atranorin (major), zeorin (major), japonene (minor or trace), salazinic acid (minor), consalazinic acid (trace).

Distribution and habitat:—Occurs on bark and on mossy rocks in tropical rainforest. Widespread in tropical to warm-temperate regions.

Remarks: — Leucodermia leucomelos is characterized by the tangled mass of elongate, linear lobes with long black marginal rhizines, the ecorticate lower surface with thickened, corticate margins, subapical soralia and the presence of salazinic acid.—Like in L. boryi , the holotype of L. leucomelos is fertile, but in both species, sorediate specimens do occur. Whether they deserve taxonomic recognition, remains an unresolved question.

Material from Thailand examined:— Loei: Phuluang Wildlife Sanctuary, Forest protection unit office, Lontae , along trail Pa Kob , before exit Tropical forest , in tropical rainforest, on bark of unidentified tree, 1254 m, 17°11'32'' N, 101°33'43'' E, 12 November 2009, S . Meesim & K . Buaruang RU-MSPL 581, ( RAMK 21123 ); ibid., S . Meesim & K . Buaruang RU-MSPL 706, ( RAMK 21155 ) .

THE LICHEN FAMILY PHYSCIACEAE IN THAILAND —II

Phytotaxa 235 (1) © 2015 Magnolia Press • 35

Figures

FIGURE 10. A. Leucodermia boryi, fertile specimen (scale 5 mm). B. Leucodermia leucomelos, sorediate specimen (scale 5 mm). C. Polyblastidium appendiculatum (scale 5 mm). D. Polyblastidium fragilissimum (scale 5 mm). E. Polyblastidium hypocaesium (scale 5 mm). F. Polyblastidium hypoleucum (scale 5 mm).