Heterodermia stellata (Vain.) W.A. Weber, Mycotaxon

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

8. Heterodermia stellata (Vain.) W.A. Weber, Mycotaxon 13: 102 (1981) ( Fig. 12F )

Anaptychia podocarpa var. stellata Vain., Acta Soc. Fauna Fl. Fenn. 7(1): 131 (1890); A. stellata (Vain.) Kurok., Beih. Nova Hedwigia 6: 90 (1962). Type — Brazil. Minas Gerais; Sitio , E.A. Vainio [Lich. Bras. Exs. No. 1080]; (lectotype, designated here: TUR-Vain. 7938!).

Thallus foliose, forming small rosettes to irregularly spreading, adnate to loosely adnate, 2–5 cm wide. Lobes 0.5–3.0 mm wide, plane to convex, short, sublinear, irregularly branched; apices plane to suberect or ascending, partially imbricate, discrete to contiguous, with whitish simple scattered cilia along the margins, 0.5–2.0 mm long, not mat-forming. Upper surface grayish white or gray, epruinose, lobulate; isidia and soredia absent; lobules marginal, more pronounced subapically, ±rounded to elongate, simple or sparingly branched, 0.05–0.30 mm wide. Medulla white. Lower surface ecorticate, arachnoid, ±canaliculate, whitish. Rhizines mainly marginal or submarginal, whitish to dark brown towards the apices, simple then digitately or fruticosely branched, 1–3 mm long. Apothecia common, subterminal, substipitate to stipitate, 1–8 mm wide; margin smooth to crenate or with ±well developed squamules, eciliate; disc brown to dark brown, often white-pruinose. Ascospores Polyblastidia - type, ellipsoidal, with 2 or 3 small sporoblastidia at either end, 30–50 × 15–25 µm. Pycnidia common, initially immersed, becoming emergent, visible as black dots; conidia bacilliform, 4–5 × 1 µm.

Chemistry: Cortex K+ yellow, C–, KC–, P+ pale yellow; medulla K+ yellow, C–, P+ pale yellow; containing atranorin (major), zeorin (major), japonene (submajor), 16β-acetoxyhopane-6α,22-diol (minor).

Nomenclature notes:— Kurokawa (1962: 90) called the specimen in TUR a holotype. But Vainio distributed No. 1080 of his exsiccate to TUR, BM, FH and Kiel ( Alava 1988) and did not select a type specimen in his original description ( Vainio 1890), so the TUR specimen has been designated a lectotype.

Distribution and habitat:—Rare on bark of trees ( Schima wallichii is reported) in hill evergreen forest and secondary forest from 830–1430 m above sea level; also in Australia, Central and South America.

Remarks: — characterized by lobes with white marginal marginal rhizines, the subterminal, substipitate or stipitate apothecia, the eciliate apothecial margin, the white, ecorticate lower surface, ascospores with sporoblastidia and by the presence of a characteristic array of triterpenes.

Material from Thailand examined:— Chiang Mai: Doi Suthep-Pui, along tourist trail at the Agricultural centre Ban Doi-Pui , in hill evergreen forest, on bark of unidentified tree, 1413 m, 18°45'04'' N, 98°53'16'' E, 30 April 2005, W . Hongsachart RU-WD 90, ( RAMK 21853 ); Nakon Ratchasima: Khao Yai National Park , along the trail from ' Mo Singh To' to former restaurant of Tourist Authority of Thailand ( TAT), in secondary forest, on Schima wallichii , 830 m, 14°24'03'' N, 101°21'58'' E, 1 June 2000, W . Polyiam RU-20023, ( RAMK 5555 ) .

The Heterodermia obscurata -group

This group is quite similar to Polyblastidium , but differs in having a lower surface with a superimposed layer of cotton-woolly hyphae, impregnated by yellow to orange-brown anthraquinone pigments ( Figs. 13B, 13D ).

The group comprises some species of Anaptychia sect. Polyblastidium ser. Polyblastidium ( Kurokawa 1962: 47) .

Remarks: A preliminary molecular phylogeny based on ITS sequences (Kalb & Lücking, in prep.) shows the distinctness of this group which clusters closer to Heterodermia s.str. than to Polyblastidium . But before describing a new genus for this group, we would like to await the results of further molecular studies based on sequences from more genes.

Figures

FIGURE 12. A. Heterodermia archeri, holotype (scale 5 mm). B. Heterodermia galactophylla, apothecia with ciliate exciple (scale 1 mm). C. Heterodermia hypochraea, holotype (scale 5 mm). D. Heterodermia incana (scale 5 mm). E. Heterodermia podocarpa (scale 1.5 mm). F. Heterodermia stellata, lectotype (scale 1 mm).

FIGURE 13. A. Heterodermia flabellata (scale 5 mm). B. Heterodermia flabellata, lower side with superimposed cotton-woolly hyphae (scale 1 mm). C. Heterodermia obscurata (scale 5 mm). D. Heterodermia obscurata, lower side with superimposed cotton woolly-hyphae (scale 1 mm).