| Arctocetraria | |
|---|---|
 | |
| Arctocetraria andrejevii | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Lecanorales |
| Family: | Parmeliaceae |
| Genus: | Arctocetraria Kärnefelt & A.Thell (1993) |
| Type species | |
| Arctocetraria andrejevii (Oxner) Kärnefelt & A.Thell (1993) | |
| Species | |
Arctocetraria is a genus of fruticose lichens in the family Parmeliaceae. It has three species. [1]
The genus Arctocetraria was circumscribed by the lichenologists Ingvar Kärnefelt and Arne Thell in 1993, who separated it from the older genus Cetraria based on distinctive reproductive features. Arctocetraria andrejevii was designated as the type species. The creation of this new genus reflected an improved understanding of evolutionary relationships among cetrarioid lichens, as Arctocetraria species share unique characteristics that set them apart from true Cetraria species, particularly in their spore-producing structures and chemical composition. [2]
The genus originally included two species (A. andrejevii and A. nigricascens), both of which were previously classified under Cetraria but were found to form their own distinct evolutionary lineage. [2] A third species was added to the genus in 2007. [3]
In 2017, Pradeep Divakar and colleagues used a then-recently developed "temporal phylogenetic" approach to identify temporal bands for specific taxonomic ranks in the family Parmeliaceae, suggesting that groups of species that diverged within the time window of 29.45–32.55 million years ago represent genera. They proposed to synonymize Arctocetraria with Nephromopsis , along with several other Parmelioid genera, so that all the genera within the Parmeliaceae are about the same age. [4] Although some of their proposed taxonomic changes were accepted, the synonymisation of the Parmelioid genera with Nephromopsis was not accepted in a later critical analysis of the temporal phylogenetic approach for fungal classification. [5]
Arctocetraria is a genus of fruticose (shrub-like) lichens in the family Parmeliaceae. These lichens grow in an upright, branching form and exhibit colours ranging from dark to pale brown, blackish, or olive-grey, with duller colouring typically appearing at their base. The main body (thallus) of Arctocetraria forms lobes that are either partially folded into channels or nearly tubular in shape. These lobes may become wider toward their tips and sometimes develop a pitted or wrinkled surface texture. Along their edges, the lobes feature scattered branched or unbranched hair-like projections called cilia . The lower surface contains small pores called pseudocyphellae, which appear either along the margins or across the surface. [2]
The outer protective layer ( cortex ) consists primarily of thick-walled cells arranged in a dense pattern, occasionally with a very thin underlying layer of elongated cells. When present, the reproductive structures (apothecia) develop along the edges of the upper surface. The spore-producing structures (asci) within the apothecia are distinctive for the genus, featuring relatively large central bodies (axial bodies) measuring 1.8–2.0 micrometres in width. [2]
The asexual reproductive structures (pycnidia) appear as small projections along the margins. These produce specialized cells (conidia) that are typically dumbbell-shaped. A key chemical characteristic of the genus is the presence of norrangiformic and rangiformic acids in the lichen tissue. [2]
The Parmeliaceae is a large and diverse family of Lecanoromycetes. With over 2700 species in 71 genera, it is the largest family of lichen-forming fungi. The most speciose genera in the family are the well-known groups: Xanthoparmelia, Usnea, Parmotrema, and Hypotrachyna.
Cetraria is a genus of fruticose lichens that associate with green algae as photobionts. Most species are found at high latitudes, occurring on sand or heath, and are characterised by their "strap-like" form with spiny lobe edges. The lobes can range from narrow and linear to broader and flattened, often forming loose or densely packed cushions. Their distinctive spiny margins serve both a defensive role and aid in vegetative reproduction through fragmentation. The genus was created by Erik Acharius in 1803 and belongs to the large family Parmeliaceae. While originally a species-rich genus, taxonomic revisions since the 1960s have split many species into new genera, though the exact circumscription remains debated among lichenologists.
Ahtiana is a fungal genus in the family Parmeliaceae. A monotypic genus, it contains the single species Ahtiana sphaerosporella, the mountain candlewax lichen, found in western North America. The species was originally classified as Parmelia sphaerosporella by Johannes Müller Argoviensis in 1891, before Trevor Goward established the new genus Ahtiana in 1985, naming it after Finnish lichenologist Teuvo Ahti. This foliose lichen is characterised by its pale yellowish-green thallus, spherical spores, laminal apothecia, and the presence of usnic and caperatic acids. It primarily grows on the bark of whitebark pine in subalpine and montane regions, though it occasionally colonises other conifers outside its preferred host's range.
Allocetraria is a genus of lichenized fungi in the family Parmeliaceae. It consists of 12 species, with a center of distribution in China.
Cetrariella is a genus of foliose lichens in the family Parmeliaceae. It contains three species.
Cetreliopsis is a genus of four species of lichens in the family Parmeliaceae.
Kaernefeltia is a genus of lichenized fungi in the family Parmeliaceae.
Masonhalea is a genus of two species of lichenized fungi in the family Parmeliaceae.
Tuckermannopsis is a genus of foliose lichens in the family Parmeliaceae.
Melanohalea is a genus of foliose lichens in the family Parmeliaceae. It contains 30 mostly Northern Hemisphere species that grow on bark or on wood. The genus is characterised by the presence of pseudocyphellae, usually on warts or on the tips of isidia, a non-pored epicortex and a medulla containing depsidones or lacking secondary metabolites. Melanohalea was circumscribed in 2004 as a segregate of the morphologically similar genus Melanelia, which was created in 1978 for certain brown Parmelia species. The methods used to estimate the evolutionary history of Melanohalea suggest that its diversification primarily occurred during the Miocene and Pliocene epochs.
Parmotrema is a genus of lichen belonging to the family Parmeliaceae. It is a large genus, containing an estimated 300 species, with a centre of diversity in subtropical regions of South America and the Pacific Islands.
Xanthoparmelia is a genus of foliose lichens in the family Parmeliaceae. This genus of lichen is commonly found in the United States, South America, southern Africa, Europe, Australia, and New Zealand.
Cetrariopsis is a genus of foliose lichens in the large family Parmeliaceae. The genus contains three species, including the type, Cetrariopsis wallichiana.
Tuckermanella is a genus of lichen-forming fungi in the family Parmeliaceae.
Coelopogon is a genus of lichen-forming fungi in the family Parmeliaceae. The genus contains two species found in southern South America and South Africa.
Esslingeriana is a fungal genus in the family Parmeliaceae. The genus is monotypic, containing the single foliose lichen species Esslingeriana idahoensis, commonly known as the tinted rag lichen. It is found in northwestern North America.
Usnocetraria is a small genus of lichen-forming fungi in the family Parmeliaceae. It contains two species of corticolous (bark-dwelling), foliose lichens.
Allocetraria corrugata is a species of foliose lichen in the family Parmeliaceae. It is found in high-elevation locations in Yunnan, China, where it grows on rocks with mosses.
Cetraria arenaria, commonly known as the sand-loving Iceland lichen, is a species of terricolous (ground-dwelling), fruticose lichen in the family Parmeliaceae. It was formally described as a new species in 1977 by the Norwegian lichenologist Ingvar Kärnefelt. The type specimen was collected in 1949 by Henry Imshaug from Mackinac County, Michigan, where he found it growing on sandy soil.
Cetraria sepincola, the chestnut wrinkle-lichen, is a species of foliose lichen in the family Parmeliaceae. It forms compact, cushion-like colonies typically 0.5–2 cm high, with a yellowish-green to dark brown upper surface and lighter underside. The species has a primarily circumboreal distribution and is widespread in northern regions, occurring from Alaska to northern California in North America and documented as far south as Argentina. While mainly found growing on woody species like Betula, Sorbus, Salix, and Alnus in bog environments and open areas, it can occasionally be found on dead wood and rarely on rock surfaces. Originally described by Jakob Friedrich Ehrhart in 1783 as Lichen sepincola, it was transferred to the genus Cetraria by Erik Acharius in 1803.
