Phyllobathelium (Müll. Arg.) Müll. Arg., Flora 73: 195 (1890).
MycoBank number: MB 4057; Index Fungorum number: IF 4057; Facesoffungi number: FoF 08877; five morphologically delimited species (Lücking et al. 2017); molecular data available for one species (Nelsen et al. 2011a).
Lichenized on leaves or rarely on bark in terrestrial, lowland to lower montane tropical to subtropical forests. Thallus corticate, grey-green with characteristic metallic appearance, often minutely verrucose. Photobiont Trentepohlia. Sexual morph: Ascomata perithecia, scattered, prominent to sessile, wart-shaped but often irregularly bumpy, immersed in pseudostromata covered by thallus layer and usually filled with a mass of black, powdery crystals, ostiolate. Involucrellum reduced. Excipulum prosoplectenchymatous, colourless. Hamathecium comprising 1.5–2 µm wide paraphyses, hyaline, flexuose, unbranched to sparsely branched. Asci 8-spored, bitunicate, fissitunicate, broadly cylindrical, shortly pedicellate, with broad ocular chamber, non-amyloid. Ascospores irregularly arranged to uni- or 2-seriate, fusiform to ellipsoid, hyaline, muriform, with thin eusepta and rectangular lumina, smooth-walled, often constricted at the septa. Asexual morph: Pycnidia common, immersed in slightly raised, applanate to conical pseudostromata filled with black, powdery crystals, visible as brown to black dots, often whole thalli only producing pycnidia. Conidia acrogenous, only macroconidia known; macroconidia septate to muriform, ellipsoid to bacillar, with more or less ciliate but rather thick gelatinous appendages, hyaline.
Chemistry: Unidentified black, powdery crystals in ascomata warts and pycnidial pseudostromata.
Type species: Phyllobathelium epiphyllum (Müll. Arg.) Müll. Arg. [= Phyllobathelium firmum (Stirt.) Vězda in Lücking & Kalb, Bot. Jb. 122: 44 (2000)].
Notes: For a detailed discussion of this genus, see Lücking (2008) and Lücking & Nelsen (in Hyde et al. 2013; Strigulaceae). Over time, 13 taxa, including 11 at species level, have been assigned to Phyllobathelium. Of these, two were subsequently transferred to Strigula (Harris 1995) and are currently treated in Swinscowia (see below), namely P. albolinitum (Nyl.) H. Mayrhofer and P. obtectum (Vain.) H. Mayrhofer. Phyllobathelium nudum Zahlbr. was recognized as a second species of Phyllocratera (Lücking & Sérusiaux 2013). Of the remaining ten names, P. epiphyllum (Müll. Arg.) Müll. Arg. and P. epiphyllum var. majus F. Schill. are synonyms of P. firmum (Stirt.) Vězda, and P. thaxteri (Vain.) Zahlbr., P. thaxteri var. heterogena (Vain.) Zahlbr., and P. megapotamicum (Malme) R. Sant. are synonymous with P. chlorogastricum (Müll. Arg.) Aptroot & Lücking (Lücking 2008; Aptroot and Lücking 2016). This leaves five species currently accepted in the genus, including also P. anomalum Lücking, P. leguminosae (Cavalc. & A.A. Silva) Lücking & Sérus., and P. nigrum R. Sant. & Tibell. The pseudostromatic perithecia with black, crystalline medulla are particularly well-developed in P. firmum and P. chlorogastricum, whereas in the other three species, the perithecia appear naked, with only remnants of a black medullary mass as irregular outer cover on the perithecia. The macroconidia of Phyllobathelium chlorogastricum are perhaps the largest known among all fungi, reaching 200 × 35 µm in size (Lücking 2008, as P. thaxteri).
Species