Heterodermia rubescens (Räsänen) D.D. Awasthi, Geophytology

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

12. Heterodermia rubescens (Räsänen) D.D. Awasthi, Geophytology 3(1): 114 (1973) ( Fig. 8E )

Anaptychia hypoleuca f. rubescens Räsänen, Arch. Soc. Zool. Bot. Fenn. 'Vanamo' 5(1): 27 (1950). Type:— INDIA. Darjeeling: E. Himalayas, 1830 m, June 1948, D.D. Awasthi 161 (holotype H!); Anaptychia esorediata f. rubescens (Räsänen) D.D. Awasthi, J. Indian Bot. Soc. 39(3): 423 (1960); Anaptychia rubescens (Räsänen) Kurokawa, Beih. Nova Hedwigia 6: 31 (1962).

Thallus foliose, orbicular to irregularly spreading, adnate to loosely adnate, to 15 cm wide. Lobes 1.0– 1.5 mm wide, plane to weakly convex or weakly concave, sublinear-elongate, sympodially to irregularly branched, contiguous or discrete at the periphery, radiating; apices not ascending, without short lateral lobes, eciliate; isidia, phyllidia and soralia absent. Upper surface whitish gray or gray, not pruinose. Medulla white. Lower surface corticate, whitish to pale brown to dirty brown towards the centre, smooth to weakly corrugated. Lower surface rhizines and marginal rhizines comparatively sparse, the latter sometimes projecting from the thallus, concolorous with the thallus or darkening at the apices, simple or irregularly or squarrosely branched. Apothecia laminal, sessile to substipitate, 1.0–5.0 mm wide; margin entire, crenulate to lobulate; disc concave, brown to brown-black, epruinose. Ascospores Pachysporaria - type, ellipsoidal, 23−30 × 11−14 µm. Pycnidia rare, immersed or slightly protruding; conidia bacilliform, 3–4 × 1 µm.

Chemistry: Cortex K+ yellow, C–, KC–, P+ yellow; medulla K+ yellow then red, C–, P+ yellow; containing atranorin (major), zeorin (major), norstictic acid (major), connorstictic acid (submajor) and 16β-acetoxyhopane- 6α,22-diol (major).

Distribution and habitat:—Grows on bark of trees ( Betula alnoides and Quercus incana are reported) in India and Thailand in lower montane forest and hill evergreen forest from 1470–1745 m above sea level; new addition to the Thai lichen biota.

Remarks:—characterized by the narrow, sublinear-elongate lobes, the lack of isidia, phyllidia and soralia and the presence of norstictic acid (major), connorstictic acid (submajor) and 16β-acetoxyhopane-6α,22-diol (minor) in the medulla. Kurokawa (1962) also found salazinic acid, but this might have been confused with connorstictic acid. H. diademata is very similar in overall habit, but is readily separated by the lack of norstictic acid.

Material from Thailand examined:— Nan: Doi Phu Kha, area of view point at Doi Phu Kha , in hill evergreen forest, on bark of Betula alnoides , 1470 m, 19°18'13'' N, 101°09'55'' E, 10 May 2006, S . Meesim RU-DK 4, ( RAMK 21476 ); ibid., S . Meesim RU-DK 11, ( RAMK 21386 ); Phitsanulok: Phu Hin Rongkla National Park, along the trail around the Phu Man Khaow , in lower montane forest, on bark of Betula alnoides , 1745 m, 16°54'23'' N, 101°05'38'' E, 2 April 2004, T . Deansa RU-TD 53, ( RAMK 21451 ) .

Heterodermia rugulosa (Kurok.) Wetmore, Bryologist 79: 304 (1976) ( Fig. 8F )

Anaptychia rugulosa Kurok., Beih. Nova Hedwigia, 6: 41 (1962). Type:— MEXICO. Jalisco: Guadalajara , on Bursera trees, 29 July 1902, Pringle 15372 (holotype US, isotype TNS; fide Kurokawa 1962).

Thallus foliose, orbicular to irregularly spreading, adnate to loosely adnate, to 10 cm wide. Lobes 0.7–2 mm wide, plane to weakly convex or weakly concave, sublinear-elongate, dichotomously to irregularly branched, contiguous or discrete at the periphery, radiating; apices not ascending, eciliate; isidia, phyllidia and soralia absent. Upper surface greenish white, densely white pruinose, centrally with short lateral flat or knobby lobules. Medulla white, patchily yellow. Lower surface corticate, whitish to pale brown to dirty brown towards the centre, smooth to strongly corrugated. Lower surface rhizines and marginal rhizines numerous, the latter projecting from the thallus, concolorous with the thallus or darkening at the apices, simple or irregularly or squarrosely branched. Apothecia laminal, sessile to substipitate, 1.5–6 mm wide; margin entire, crenulate to lobulate; disc concave, brown to brown-black, epruinose. Ascospores Pachysporaria - type, ellipsoidal, 19−28 × 11−13 µm.

Chemistry: Cortex K+ yellow, C–, KC–, P+ yellow; medulla K+ yellow, C–, P–; containing atranorin (major), zeorin (major), leucotylin (minor), yellow pigment (7-chloroemodin).

28 • Phytotaxa 235 (1) © 2015 Magnolia Press

MONGKOLSUK ET AL.

Distribution and habitat:—Grows on the bark of trees in North America and Mexico.

Remarks:—characterized by the narrow, sublinear-elongate lobes, the lack of isidia, phyllidia and soralia and the presence of 7-chloroemodin in the medulla. Heterodermia diademata is very similar, but differs in lacking the yellow pigment in the medulla.

Figures

FIGURE 8. A. Heterodermia koyana (scale 5 mm). B. Heterodermia koyanoides (scale 5 mm). C. Heterodermia lepidota (scale 5 mm). D. Heterodermia pseudospeciosa (scale 5 mm). E. Heterodermia rubescens (scale 5 mm). F. Heterodermia rugulosa (scale 5 mm).