Biatora

Biatora is a genus of lichens in the family Ramalinaceae. Originally circumscribed in 1817, the genus consists of crustose and squamulose lichens with green algal photobionts, biatorine apothecia, colorless, simple to 3-septate ascospores, and bacilliform pycnospores.

Description

Biatora species are crustose lichens with a spreading (Template:Lichengloss) thallus that may appear thin and somewhat membranous in places. The surface is often cracked (Template:Lichengloss) and, in species that grow in association with mosses, may be Template:Lichengloss or warted. The thallus is typically creamy white, dull green, glaucous green, or green-grey and lacks a distinct outer protective layer (Template:Lichengloss). Some species produce soredia, small reproductive Template:Lichengloss that facilitate dispersal. A Template:Lichengloss, the initial fungal layer that some lichens form before developing a full thallus, is absent. The photosynthetic partner (Template:Lichengloss) is a Template:Lichengloss alga, a group characterized by spherical to broadly ellipsoidal cells.

The reproductive structures (apothecia) are Template:Lichengloss, meaning they lack a Template:Lichengloss derived from the lichen thallus itself. They are Template:Lichengloss or closely Template:Lichengloss to the surface and range from weakly to strongly convex. In some species, the apothecia are initially flat with a shallow margin but later become Template:Lichengloss (without a distinct border). Their colour varies widely, including light beige, dark reddish brown, green-grey, bluish green, or khaki. Black apothecia are rare but, when present, have a green or blue tint when wet. Most species lack Template:Lichengloss, the powdery surface coating found on some lichens.

A well-developed Template:Lichengloss (the outer tissue of the apothecium) is present but becomes reflexed over time. It consists of tightly packed, radiating hyphae embedded in a gel matrix that remains stable in potassium hydroxide (K) solution and does not swell. The outer edge may be coated with a thin gel layer. The hymenium, where spores develop, is 30–100 μm tall and typically lacks a distinct Template:Lichengloss (uppermost layer), though some species show pale pigmentation at the top. It does not contain granules or oil droplets and reacts with iodine (I+), staining red-brown when young and blue in older herbarium specimens. Below the hymenium, the Template:Lichengloss is distinct and slightly opaque due to the presence of ascogenous hyphae (spore-producing structures). The Template:Lichengloss, a supporting tissue beneath the hymenium, consists of interwoven hyphae embedded in a dense gel matrix.

The paraphyses, sterile filamentous structures within the hymenium, are coherent in KOH, have narrow Template:Lichengloss (0.5–2.5 μm wide), and are mostly unbranched, though occasional branching or connections (anastomoses) occur. The tips of the paraphyses are slightly swollen, sometimes reaching up to 5 μm in diameter, and rarely bear a distinct cap or hood. The asci, where spores develop, contain eight spores and have a Biatora-type structure. They feature a blue-staining (K/I+) apical dome penetrated from below by a non-staining (K/I–) apical cushion, which is surrounded by a deeply blue-staining zone. The ascus walls themselves do not stain in K/I but are surrounded by an outer layer that reacts red-brown in iodine (I+) and blue in K/I. The ocular chamber, an internal structure within the ascus, is relatively small.

The Template:Lichengloss are colourless, with a shape ranging from ellipsoidal to Template:Lichengloss (thread-like) or Template:Lichengloss (spindle-shaped). They may be aseptate (lacking internal divisions) or have between one and seven septa. The spores are smooth and do not possess a distinct outer coating (Template:Lichengloss). Asexual reproduction occurs via conidia, which are produced in small, flask-shaped reproductive structures called pycnidia. These structures are Template:Lichengloss within the thallus and have an unpigmented or weakly pigmented wall, similar in colour to the hymenium. The conidia themselves are colourless, aseptate, and Template:Lichengloss (rod-shaped).

Chemically, Biatora lichens can contain a variety of secondary metabolites, including gyrophoric acid and argopsin, and less commonly, other depsides, depsidones, xanthones, or usnic acid. Some species, however, lack detectable secondary metabolites when analysed using thin-layer chromatography.

Species

• Biatora alaskana Printzen & Tønsberg (2000)
• Biatora alnetorum S.Ekman & Tønsberg (2019)
• Biatora amylacea Palice, Malíček, Vondrák & Printzen (2023) – Europe
• Biatora appalachensis Printzen & Tønsberg (2004)
• Biatora aureolepra T.Sprib. & Tønsberg (2009)
• Biatora australis Rodr.Flakus & Printzen (2016)
• Biatora bacidioides Printzen & Tønsberg (2003)
• Biatora britannica Printzen, Lumbsch & Orange (2001)
• Biatora carneoalbida (Müll. Arg.) Coppins (1992)
• Biatora chrysantha (Zahlbr.) Printzen (1994)

• Biatora chrysanthoides Printzen & Tønsberg (2003)
• Biatora cuprea (Sommerf.) Fr. (1831)
• Biatora cuyabensis (Malme) S.Y.Kondr. (2019)
• Biatora efflorescens (Hedl.) Räsänen (1935)
• Biatora ementiens (Nyl.) Printzen (2014)
• Biatora epirotica Printzen & T.Sprib. (2011)
• Biatora epixanthoides (Nyl.) Diederich (1989)
• Biatora globulosa (Flörke) Fr. (1845)
• Biatora hafellneri Rodr.Flakus & Printzen (2016)
• Biatora halei (Tuck.) S.Y.Kondr. (2019)
• Biatora hemipolia (Nyl.) S.Ekman & Printzen (2014)
• Biatora ivanpisutii S.Y.Kondr., Lőkös & Hur (2016)
• Biatora kalbii (Brako) S.Y.Kondr. (2019)
• Biatora kodiakensis Printzen & Tønsberg (2004)
• Biatora ligni-mollis T.Sprib. & Printzen (2009)
• Biatora loekoesiana S.Y.Kondr. & Hur (2018)
• Biatora longispora (Degel.) Lendemer & Printzen (2019)
• Biatora meiocarpa (Nyl.) Arnold (1887)
• Biatora nobilis Printzen & Tønsberg (2000)
• Biatora oligocarpa Printzen & Tønsberg (2004)
• Biatora oxneri (S.Y.Kondr., L.Lőkös & Hur) Printzen & Kistenich (2018)
• Biatora pacifica Printzen, Tønsberg & G.Thor (2016)
• Biatora pallens (Kullh.) Printzen (2005)
• Biatora pausiaca Printzen & Tønsberg (2003)
• Biatora pontica Printzen & Tønsberg (2003)
• Biatora printzenii Tønsberg (2002)
• Biatora pseudosambuci (S.Y.Kondr., Lőkös & Hur) S.Y.Kondr., Lőkös & Hur (2016)
• Biatora pycnidiata Printzen & Tønsberg (2004)
• Biatora radicicola Printzen, Palice & J.P.Halda (2016)
• Biatora subduplex (Nyl.) Printzen (1995)
• Biatora subhispidula (Nyl.) S.Y.Kondr. (2019)
• Biatora terrae-novae Printzen & J.W.McCarthy (2016)
• Biatora toensbergii Holien & Printzen (1995)
• Biatora vernalis (L.) Fr. (1882)
• Biatora veteranorum Coppins & Sérus. (2010)
• Biatora vezdana S.Y.Kondr. (2019)

The taxon Biatora marmorea, found in Alaska, was proposed as a new species in 2020; however, it is an illegitimate name as it had already been used for a species that is now known as Bagliettoa marmorea.