| Pyxine petricola | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Caliciales |
| Family: | Caliciaceae |
| Genus: | Pyxine |
| Species: | P. petricola |
| Binomial name | |
| Pyxine petricola Nyl. (1876) | |
| Synonyms [1] | |
Pyxine petricola is a species of saxicolous (rock-dwelling), foliose lichen in the family Caliciaceae. [2] The distribution of the lichen includes Australia, East Africa, North and Central America, and the Philippines. [3]
The lichen was formally described as a new species in 1876 by the Finish lichenologist William Nylander. In Nylander's brief description, he mentions that Pyxine petricola has a slightly blue-green thallus, spreading thinly and attaching closely to surfaces. Its reproductive structures, apothecia, are black, flat, and edged, with dark, oblong, two-compartment spores. The top cell layer of the apothecium is bluish-black, contrasting with the nearly colourless layer beneath. He further notes that the species typically grows on rocks. [4]
The thallus of Pyxine petricola, the lichen typically does not exceed a diameter of 40 mm (1.6 in) and features a thallus with irregular or radially arranged lobes . These lobes, measuring between 0.3 and 1.2 mm in width, are white or greyish white in colour and have a branching pattern that is somewhat dichotomous (splitting into two parts) and often overlapping ( imbricate ), lying flat against or slightly raised from the surface. The thallus may be smooth or slightly convex, with pseudocyphellae—specialised pores allowing gas exchange—visible as white lines along the margins and upper surface, sometimes forming a network ( reticulate ). Unlike some lichens, Pyxine petricola does not develop isidia (outgrowths for reproduction and dispersal) or pustules , and may or may not be covered in a fine powder ( pruina ). The inner tissue (medulla) of the lichen is white. [3]
Reproductive structures (apothecia) are commonly found within the lichen, often incorporating algae within their outer rim ( exciple ) and featuring an internal structure (stipe) that turns red when treated with a potassium hydroxide solution (i.e., the K spot test). The ascospores measure 12–20 by 6–8 μm. [3]
Chemically, Pyxine petricola is distinguished by the presence of lichexanthone and triterpenes. The outer layer (cortex) of the lichen fluoresces yellow under ultraviolet light but is K- and Pd-. [3]
Collema is a genus of lichens in the family Collemataceae. The photobiont is the cyanobacterium genus Nostoc. Species in this genus typically grow on nutrient-rich bark or somewhat siliceous or calcareous rocks in humid environments.
Physcia is a genus of lichen-forming fungi in the family Physciaceae. The widely distributed genus contains about 80 species. The genus is cosmopolitan, and has been extensively studied in various regions in the past several decades, with significant biodiversity in South America identified as a central diversity hotspot. Physcia species are foliose, lobate lichens that grow with a loose to close appressed habit. Their upper surface is typically whitish, pale greenish, green-grey, or dark grey in colour. The thallus colour remains relatively unchanged when moistened. Physcia lichens typically grow on bark, on wood, or rock, although they have occasionally been recorded dwelling on man-made structures. They thrive in nutrient-rich environments and are expanding rapidly in urban areas of the United Kingdom previously affected by SO2 pollution.
Xanthoparmelia is a genus of foliose lichens in the family Parmeliaceae. This genus of lichen is commonly found in the United States, as well as Australia, New Zealand and Ecuador.
Bulbothrix meizospora is a species of foliose lichen in the family Parmeliaceae. It is found in Africa, Asia, and South America, where it grows on tree bark.
Pyxine sorediata, commonly known as mustard lichen, is a widely distributed species of foliose lichen in the family Caliciaceae. It has a subtropical to warm temperate distribution, and grows on bark, rocks, and moss as substrates. Pyxine sorediata has been reported from regions of North America, Europe, Africa, Asia, and Australasia.
Pyxine cocoes, the buttoned rosette lichen, is a widely distributed species of foliose lichen in the family Caliciaceae.
Pyxine subcinerea is a species of foliose lichen in the family Caliciaceae. It has a pantropical distribution, and typically grows on bark, but less commonly on rocks. The lichen is characterised by its yellow medulla, soralia on the margins on the lobes that make up the thallus, and the presence of the chemical lichexanthone in the cortex.
Punctelia hypoleucites, commonly known as the southwestern speckled shield lichen, is a species of foliose (leafy) lichen in the family Parmeliaceae. First formally described by Finnish botanist William Nylander as a species of Parmelia, it was transferred to the genus Punctelia in 1982. The lichen is found in Africa, North America, and South America, where it grows on the bark of both hardwood and coniferous trees. Its greenish-grey thallus is covered with tiny white pseudocyphellae – minute holes in the thallus surface that facilitate gas exchange. Some macroscopic features that help distinguish this species from other related members of the genus include the presence and the structure of the apothecia, the absence of asexual surface propagules, and the light brown color of the thallus undersurface. Chemically, the presence of lecanoric acid in the medulla and atranorin in the cortex help distinguish it from lookalikes.
Parmelia fraudans is a species of foliose lichen in the family Parmeliaceae. It is found in Europe and North America, where it grows on rocks.
Canoparmelia consanguinea is a species of saxicolous (rock-dwelling), foliose lichen in the family Parmeliaceae. Found in Brazil, it was formally described as a new species in 2009 by lichenologists Marcelo Marcelli, Luciana da Silva Canêz, and John Elix. The type specimen was collected from an open field in Fazenda da Estrela at an altitude of 920 m (3,020 ft), where it was growing on basaltic rock.
Placolecis kunmingensis is a species of saxicolous (rock-dwelling), crustose lichen in the family Catillariaceae. It is found in Yunnan, China. The lichen is characterised by a thallus that is areolate to squamulose in its centre, forming irregular patches or clumps 10–50 mm wide, as well as its ellipsoid or spherical ascospores with slightly thickened wall.
Placolecis sublaevis is a species of saxicolous (rock-dwelling), crustose lichen in the family Catillariaceae. It is found in Yunnan and Sichuan, China. The crust-like, radiating body of the lichen forms irregular patches or clumps and includes numerous false conidiomata, a type of asexual reproductive structure, within its thallus. Its lobes, dark brown and slightly flattened at the top, form larger groups at the edges and contain an upper layer composed of loosely interwoven cells and a lower inner tissue that varies from reddish-orange to white.
Tetramelas gariwerdensis is a species of saxicolous (rock-dwelling), crustose lichen in the family Physciaceae, described in 2020. It is found in the Grampian Mountains in western Victoria, Australia.
Buellia cravenii is a species of saxicolous (rock-dwelling), crustose lichen in the family Caliciaceae. It is found in Australia. The lichen spreads up to 3.5 cm wide thick, forming a continuous, grey-white cracked pattern of areoles.
Buellia eldridgei is a rare species of terricolous (ground-dwelling), crustose lichen in the family Caliciaceae, known to occur only in Queensland, Australia.
Buellia lordhowensis is a little-known saxicolous (rock-dwelling), crustose lichen species in the family Caliciaceae, first described in 2020. It is only known to occur on Lord Howe Island, Australia.
Buellia subalbula is a species of saxicolous (rock-dwelling), crustose lichen in the family Caliciaceae. It occurs in coastal southern Africa, South America, and Australia, where it grows on calcareous rocks.
Baeomyces heteromorphus is a species of terricolous (ground-dwelling) lichen in the family Baeomycetaceae. It has an Australasian distribution. Characteristics of the lichen include its greenish-grey thallus, the pink to brownish discs of its apothecia, translucent spores lacking internal partitions (septa), and the presence of the secondary metabolites norstictic acid and connorstictic acid.
Caloplaca lecapustulata is a species of saxicolous (rock-dwelling), crustose lichen in the family Teloschistaceae. Found in Brazil, it was described as a new species in 2016.
Teloschistes spinosus is a species of corticolous (bark-dwelling), fruticose lichen in the family Teloschistaceae. It is found in Australia and New Zealand.