Heterodermia albicans (Pers.) Swinscow & Krog, Lichenologist

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

1. Heterodermia albicans (Pers.) Swinscow & Krog, Lichenologist 8: 113 (1976) ( Fig. 2F )

Parmelia albicans Pers., Ann. Wetterauischen Ges. gesammte Naturk. 2(1): 17 (1810). Type:—ST. DOMINGO [ Haiti]. Poiteau s.n. (holotype L, fide Swinscow & Krog 1988); Physcia albicans (Pers.) J.W. Thomson, Beih. Nova Hedwigia 7: 88 (1963).— Parmelia domingensis Ach. (nom. nov. illegit.), Syn. Lich.: 212 (1814); Hagenia domingensis (Ach.) De Not., Giorn. Bot. Ital. , 2 (1), 1: 186 (1846); Anaptychia domingensis (Ach.) A. Massal., Mem. lich.: 39 (1853); Squamaria domingensis (Ach.) A. Massal., Atti Reale Ist. Veneto Sci. Lett. Arti , ser. 3, 5: 250 (1860); Physcia stellaris (L.) Nyl. var. domingensis (Ach.) Tuck., Proc. Amer. Acad. Arts 4: 396 (1860).—For further synonymy see Swinscow & Krog (1976).

Thallus foliose, orbicular to irregularly spreading, comparatively small, adnate, to 4 cm wide. Lobes 0.5–1.0 mm wide, to ca. 1.5–2.5 mm wide at the tips, ± plane to weakly convex, sublinear-elongate, usually richly dichotomously branched; lobe apices not ascending, eciliate, sorediate. Upper surface whitish gray to brownish gray, darker at the apices, occasionally sparsely pruinose; soralia white to bluish gray, forming small ± continous marginal soralia towards the thallus centre. Medulla white. Lower surface corticate, whitish to pale brown, rarely dark gray, smooth to corrugate. Lower surface rhizines frequent, evenly distributed on the lower surface, simple or irregularly branched, usually short (ca. 1 mm long), pale to dark brown or black. Apothecia very rare, laminal, substipitate, 0.5–3.0 mm wide; margin becoming sorediate; disc concave, dark brown, epruinose. Ascospores Pachysporaria - type, narrowly ellipsoidal, 21–32 × 7–14 Μ m. Pycnidia ± common, immersed, with black weakly protruding apices; conidia bacilliform, 4–6 × 1 Μ m.

Chemistry: Cortex K+ yellow, C–, KC–, P+ yellow; medulla K+ yellow then red, C–, P+ yellow-orange; containing atranorin (major), zeorin (major), 16β-acetoxyhopane-6α,22-diol (minor), leucotylin (minor), 6αacetoxyhopane-16β,22-diol (trace), salazinic acid (major), hypoconstictic acid (submajor), 3- O -methylconsalazinic acid (minor), consalazinic acid (minor) and -acetylhypoconstictic acid (minor).

Distribution and habitat:—This rare species occurs on bark in Trat Province, also rarely on rocks in Australia, North, Central and South America, Macaronesia, South Africa and China.

Remarks:— Heterodermia albicans is characterized by lobes with marginal soralia towards the thallus centre and the presence of salazinic acid and hypoconstictic acids in the medulla.

Material reported from Thailand ( Wolseley et al. 2002: 27):— Trat Province: Koh Chang Island, Gulf of Thailand, ad corticem arboris prope Lem Ngob , J. Schmidt 9, 32 .

Specimens examined: GUATEMALA. Suchitepéquetz: National Highway 11, ca. 20 km N of Patulul , on deciduous trees alongside the street, 400 m, 14°40' N, 91°07' W, 16 January 1979, K. Kalb & G. Plöbst (herb. Kalb 39583) )— BRAZIL. Paraná: Guaíra, in a rainforest along Rio Paraná, 200 m, 24°05’ S, 54°15’ W, 9 August 1980, K. Kalb & m, Marcelli (herb. Kalb 39569) — BRAZIL. São Paulo: Serra do Mar; ca. 20 km E of Cruzeiro , in a light and relatively dry secondary rainforest, 1600 m, 22°33' S, 44°45' W, 3 November 1978, K. Kalb & G. Plöbst (herb. Kalb 40303) .

Heterodermia albidiflava (Kurok.) D.D. Awasthi, Geophytology 3(1): 113 (1973)

Anaptychia albidiflava Kurok., Beih. Nova Hedwigia 6: 42 (1962); Type :— INDIA. Darjeeling: above Kurseong, on tree trunk, 1680 m, Awasthi 3912 (holotype LWG-Awas., fide Awasthi 1962).

Remarks: —Species not recorded for Thailand are not numbered, but selected specimens studied for morphological, anatomical and chemical characters are cited. This species is almost identical to H. firmula (see below), but differs chemically in containing dissectic acid. We have not seen any authentic material. All specimens identified as H. albidiflava studied by us turned out to be H. firmula and lacked dissectic acid.

Figures

FIGURE 2. A. Heterodermia verdonii, thallus lobes with pseudocyphellae along margins (see arrows), (scale 1 mm). B. Heterodermia verdonii, pseudocyphellae along margin of apothecia (scale 1 mm). C. Polyblastidium fragilissimum, flattened marginal lobuli, ecorticate below (scale 1 mm). D. Heterodermia isidiophora, ± cylindrical isidia, completely corticate. E. Heterodermia antillarum, radial symmetric isidia, partly flattened, completely corticate. F. Heterodermia albicans, marginal soralia with granular soredia (scale 1 mm).