Trypetheliaceae Eschw., Syst. Lich.: 17 (1824)

MycoBank number: MB 81884; Index Fungorum number: IF 81884; Facesoffungi number: FoF 08784; approximately 440 species (Aptroot and Lücking 2016; Aptroot et al. 2016, 2019; Lücking et al. 2017; this paper).

Synonym: Arthopyreniaceae Walt. Watson

Lichenized or more rarely saprobic on bark or rarely on bryophytes over the soil; in terrestrial, chiefly lowland to lower montane tropical habitats, with few species extending into temperate regions. Thallus reduced and decorticate, white, to distinctly corticate, yellow-brown to olive-green, sometimes partly or completely bright yellow, orange or red due to superficial anthraquinone pigments. Photobiont Trentepohlia. Ascomata scattered, clustered, aggregated in pseudostromata, or fused with common ostiole, immersed to sessile, brown-black but usually covered by thallus, globose to pear-shaped or conical, coriaceous to carbonaceous, ostiolate, ostiole round. Excipulum dense, consisting of compressed hyphae, appearing prosoplectenchymatous in thin, bleached sections but structure usually difficult to observe due to heavy carbonization, generally dark brown to brown-black. Hamathecium comprising 0.5–0.7(–1.5) µm wide paraphysoids, hyaline, straight or rarely flexuose, branched and usually anastomosing, usually embedded in a thick, gelatinous matrix, occasionally with hyaline or yellow oil inspersion. Asci 1–8-spored, bitunicate, fissitunicate, obclavate to cylindrical, short pedicellate, with refractive ring and very wide, non-amyloid ocular chamber comprising more than half of the width of the ascus. Ascospores irregularly arranged to biseriate, fusiform-ellipsoid to oblong, hyaline to dark brown, septate to muriform, with distosepta and sometimes additional eusepta and rectangular to diamond-shaped (generally six-angled) lumina, smooth-walled or rarely ornamented, not or slightly constricted at the septa, with evanescent mucilaginous material on the outside, either as polar pads or irregular median pads or a complete sheath enveloping the whole ascospore. Pycnidia known from a few species, immersed, visible as black dots in specific, often pseudostromatic areas on fertile thalli, or whole thalli only producing pycnidia; rarely old ascospores within asci transforming into pycnidia. Conidia acrogenous, hyaline, aseptate, bacillar.

Chemistry: lichexanthone is sometimes produced on the thallus surface; yellow to orange or red anthraquinones and perylenequinones are often produced in the medulla of the thalline layer covering the perithecia and sometimes in the thallus medulla or superficial on various parts of the thallus.

Type: Trypethelium Spreng.

Notes: Trypetheliaceae (Zenker in Goebel and Kunze 1827) is one of the oldest described families of lichenized Ascomycota. Its delimitation was obscure throughout the past nearly 200 years, but in general the family included pyrenocarpous, epiphytic lichens with crustose thalli containing a Trentepohlia photobiont, anastomosing paraphysoids forming a network embedded in a gelatinous matrix, bitunicate asci, and hyaline, distoseptate ascospores with diamond-shaped lumina (Aptroot 1991; Harris 1995; Aptroot et al. 2008; Sweetwood et al. 2012). Several genera that had been included at some point have subsequently been placed in other families, such as Megalotremis, Ornatopyrenis, and Trypetheliopsis (Aptroot 1991; Harris 1995; Lumbsch and Huhndorf 2010). Traditionally, the family included seven core genera: Pseudopyrenula (ecorticate; ascospores astrothelioid), Polymeridium (ecorticate; ascospores euseptate), Trypethelium (corticate; ascomata with apical ostiole; ascospores astrothelioid, transversely septate), Laurera (corticate; ascomata with apical ostiole; ascospores astrothelioid, muriform), Astrothelium (corticate; ascomata with lateral or shared ostiole; ascospores astrothelioid, transversely septate), Campylothelium (corticate; ascomata with lateral ostiole; ascospores astrothelioid, muriform), and Cryptothelium (corticate; ascomata with shared ostiole; ascospores astrothelioid, muriform). Four additional genera were included or recognized in more recent treatments (Aptroot 1991; Tucker and Harris 1980; Harris 1986, 1995; Lücking et al. 2007): Exiliseptum (corticate; ascomata with shared ostiole; ascospores euseptate), Bathelium (corticate; ascomata pseudostromatic, with walls composed of brown, jigsaw-puzzle-shaped hyphal cells), Architrypethelium (corticate; ascomata with apical or lateral ostiole; ascospores transversely septate, very large, hyaline or brown), and Aptrootia (corticate; ascomata with apical ostiole; ascospores muriform, dark brown).