Arthopyrenia
Arthopyrenia is a genus of fungi in the family Trypetheliaceae. It was formerly classified in the eponymic family Arthopyreniaceae, but molecular phylogenetics studies showed that the type species, Arthopyrenia cerasi, was a member of the Trypetheliaceae. Arthopyrenia fungi typically form inconspicuous films embedded within tree bark and produce tiny, flask-shaped fruiting bodies covered by dark, shield-like caps. The genus includes both lichen-forming species and non-lichenized species, with about 100 currently recognized species found primarily on bark and wood substrates.
Description
Arthopyrenia forms an immersed thallus, essentially a film sunk into the outer bark, which is usually inconspicuous or only slightly paler than the surrounding tissue and spreads in a diffuse patch. It is not lichenised. The sexual fruit bodies are perithecia, circular to elliptical in surface view. They are covered by a dark, often laterally spreading, clypeate —a shield-like cap made of compacted fungal hyphae intermingled with bark cells—and surrounded internally by a thin, usually colourless . The hyphae are dark brown and react K+ in potassium hydroxide. The tissue between and above the asci consists of robust, thick-walled —sterile threads that are sparsely branched, occasionally connected to one another, and only distantly partitioned by cross-walls; the gelatinous matrix of the hymenium is iodine-negative.The asci are, meaning they have two functional wall layers that separate during spore release; they are roughly cylindrical, with an apical, and do not stain in iodine. Each ascus bears eight spores. The ascospores are clavate to cylindric-clavate, with one or three cross-walls and a strong narrowing at each septum; they are colourless and smooth when young, sometimes becoming faintly brown and minutely warted in old age. A broad, persistent gelatinous sheath surrounds each spore, a feature that can aid recognition in section.
Asexual reproduction occurs in pycnidia—minute, blackish, flask-like structures whose walls contain the same dark pigment as the perithecial involucrellum. The conidiogenous cells are variably shaped—cylindrical, flask-shaped, or nearly spherical—and often proliferate percurrently, extending through the old opening to make a new one like the telescoping of a pen. The resulting conidia are colourless, cylindrical to bacilliform, and either lack septae or have three; some species produce two distinct asexual spore types. No secondary metabolites are detected by thin-layer chromatography.
Description
Arthopyrenia includes both lichenised and saprobic species. Where lichenised, the photobiont is a trentepohlioid alga; in other species no is present. The thallus is usually crustose and largely immersed in the bark or wood, but in some taxa it is reduced to a thin, cover formed by a black, and it can also be absent.The sexual structures are perithecial ascomata that appear circular to ellipsoid in surface view. A dark-brown, overlies the fruiting body and is composed of compressed fungal hyphae mixed with host bark cells. The true ascomatal wall is black and becomes discontinuous beneath the. A thin, usually colourless surrounds the central cavity. The hamathecium comprises branched, anastomosing, sometimes bead-like that are typically non-amyloid; in some species these elements partly dissolve, and the remaining material may stain amyloid. are also present around the ostiole.
The asci are, to, with an apical ; they are non-amyloid and contain eight ascospores. The ascospores are usually hyaline, pyriform to clavate, and 1–3-septate with true septa ; walls may bear minute wart-like ornamentation. Reported spore dimensions are about 4–16 × 12–50 μm. Asexual reproduction occurs in blackish pycnidia producing conidia that are simple or 1–3-septate, variously oblong, ovoid,, or thread-like. No lichen secondary metabolites are known from the genus.
Species
, Species Fungorum accepts 99 species of Arthopyrenia:Arthopyrenia agasthiensis Arthopyrenia algovica Arthopyrenia aloes Arthopyrenia alpivaga Arthopyrenia amaura Arthopyrenia amphilomatis Arthopyrenia analepta Arthopyrenia aphorisasa Arthopyrenia arnoldii Arthopyrenia atricolor Arthopyrenia atroalba Arthopyrenia betulicola Arthopyrenia biroi Arthopyrenia bispora Arthopyrenia bukowinensis Arthopyrenia calcicola Arthopyrenia callunae Arthopyrenia carneobrunneola Arthopyrenia cerasi Arthopyrenia ceylonensis Arthopyrenia cinereopruinosa Arthopyrenia claviformis Arthopyrenia colleta Arthopyrenia contraria Arthopyrenia coppinsii Arthopyrenia degelii Arthopyrenia desistens Arthopyrenia dirumpens Arthopyrenia elachistotera Arthopyrenia exasperata Arthopyrenia fallacior Arthopyrenia fallaciosa Arthopyrenia gravastella Arthopyrenia grisea Arthopyrenia keralensis Arthopyrenia macquariensis Arthopyrenia maritima Arthopyrenia minor Arthopyrenia naevia Arthopyrenia novae-guineae Arthopyrenia oblongens Arthopyrenia pandanicola Arthopyrenia picconii Arthopyrenia platypyrenia Arthopyrenia plumbaria Arthopyrenia praetermissa Arthopyrenia salicis Arthopyrenia spilobola Arthopyrenia stenotheca Arthopyrenia stigmatophora Arthopyrenia subcerasi Arthopyrenia subfallaciosa Arthopyrenia subgregans Arthopyrenia subpomacea Arthopyrenia subpunctiformis Arthopyrenia subvelata Arthopyrenia taxodii Arthopyrenia texensis Arthopyrenia tuscanensis Arthopyrenia welwitschii- ''Arthopyrenia zostra''