Marchantiana

Marchantiana is a genus of lichen-forming fungi in the family Teloschistaceae. It contains seven species of corticolous (bark-dwelling), crustose lichens that occur in the Southern Hemisphere.

Taxonomy
Lichenologists Sergey Kondratyuk, Ingvar Kärnefelt, John Alan Elix, Arne Thell, and Jae-Seoun Hur circumscribed the genus Marchantiana in 2014, as part of a taxonomic revision of the subfamily Caloplacoideae of the family Teloschistaceae. They designated Marchantiana occidentalis as its type species. Initially, the genus comprised six species, all native to the Southern Hemisphere, with all but one species from Australia. The genus was named in honour of the Australian botanist Neville Graeme Marchant, to acknowledge his extensive contributions to the flora of Western Australia.

In their 2014 study, Kondratyuk and his team utilized mitochondrial DNA for molecular analysis. Their findings suggested that while M. occidentalis holds a distinct position relative to other Marchantiana species, all species together form a well-supported monophyletic branch. Further, they suggested that Marchantiana occupied an "isolated position" in the subfamily Caloplacoideae. Further analysis in 2015 by Kondratyuk's team proposed Marchantiana to be phylogenetically nested within the subfamily Brownlielloideae, and later in 2017, within the Teloschistoideae. However, a more recent 2021 molecular analysis focusing on specific, verified genetic loci placed Marchantiana in the subfamily Caloplacoideae.

In 2023, an advanced molecular analysis using three genes revealed a close relation between Marchantiana and Yoshimuria. Sochting and colleagues noted that, while Marchantiana may seem paraphyletic, its monophyletic origin is still plausible. They concluded that classifying Marchantiana as a monophyletic group was warranted, given the taxon's unique ecology and distribution. They subsequently added two newly described twig-growing lichen species from southern Patagonia, as well as three species transferred from other genera as new combinations.

Description
Marchantiana has a crust-like thallus that can range in appearance from a continuous to a patchy texture. Its colour varies, encompassing pale grey, dark brownish-grey, dark greenish-grey, and even vibrant hues of yellow or orange. The layer is often thin and arranged in a specific cellular pattern known as. The can fall into three types:, , or. The of these structures are made of  tissue. Each reproductive sac, or ascus, contains eight spores that can are divided into 2, 3, or 4 compartments by partitions called septa. Its conidia are rod-shaped or slightly elongated rod-shaped. Standard chemical spot tests indicate the thallus either remains unchanged (K−) or turns purple (K+) when exposed to a solution of potassium hydroxide, while the apothecia consistently turn purple. The secondary chemical composition of Marchantiana includes anthraquinones associated with parietin, fragilin, or neochloroemodin groups. Other compounds like dibenzofurans, related to the ascomatic acid, and lichexanthone are sometimes present. These secondary substances are predominantly found in the reproductive structures of the lichen.

Species

 * Marchantiana asserigena
 * Marchantiana epibrya
 * Marchantiana occidentalis
 * Marchantiana pyramus
 * Marchantiana queenslandica
 * Marchantiana ramulicola
 * Marchantiana subpyracea

Former species
Marchantiana maulensis was later transferred to the genus Villophora as Villophora maulensis. Several other former Marchantiana species have been transferred to genus Streimanniella:


 * Marchantiana burneyensis is now Streimanniella burneyensis
 * Marchantiana kalbiorum is now Streimanniella kalbiorum
 * Marchantiana michelagoensis is now Streimanniella michelagoensis
 * Marchantiana seppeltii is now Streimanniella seppeltii.