| Usnea pallidocarpa | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Lecanorales |
| Family: | Parmeliaceae |
| Genus: | Usnea |
| Species: | U. pallidocarpa |
| Binomial name | |
| Usnea pallidocarpa Wirtz & Lumbsch (2011) | |
 | |
| Holotype site: Cerro Catedral, Argentina [1] | |
Usnea pallidocarpa is a species of saxicolous (rock-dwelling) beard lichen in the family Parmeliaceae. [2] It is known from Argentina.
The lichen was formally described as new to science in 2011 by the lichenologists Nora Wirtz and H. Thorsten Lumbsch. The type was collected from the Cerro Catedral in Bariloche (Río Negro), at an elevation of 1,900 m (6,200 ft). The species epithet pallidocarpa refers to the pale-coloured discs of the apothecium. [1] Molecular phylogenetics analysis suggests a close relationship with Usnea messutiae , another Usnea species from Argentina described later the same year. [3]
Usnea pallidocarpa is characterised by its shrubby, erect appearance and a thallus (the body of the lichen) that typically measures between 5 and 7 cm in length. This lichen originates from a holdfast, which is the anchoring part of the lichen, appearing either unpigmented or with a brownish hue. The main branches of the thallus taper towards the holdfast and have a somewhat dichotomous to richly branched structure with rounded ( terete ) branches. The surface of these branches is a yellow-green colour, which is both smooth and glossy, and is sparsely marked with faveoles , or tiny pits. [1]
Usnea pallidocarpa has a unique feature among some morphotypes – a "compressed" form where the side branches are thick, claw-like, and darkly pigmented, akin to the characteristics seen in U. perpusilla . The lichen's main branches lack pigmentation, while the side branches may display variegated bands of black pigment. Another aspect of this lichen is the presence of cortex annulations, or ring-like structures on the cortex, though it lacks papillae . Fibrils (small fibers) are very rare in this species. [1]
The medulla, the innermost layer of the thallus, is dense in Usnea pallidocarpa. Its central axis , a structural component, is rather thick, occupying about 34 to 71 percent of the branch diameter. Unlike some other lichen species, Usnea pallidocarpa does not produce soredia or isidiomorphs – propagules involved in asexual reproduction. [1]
This lichen frequently develops apothecia, which are spore-producing structures. These are typically found in more or less terminal positions on the branches, though they can occasionally occur in series. As they mature, the apothecia transition from a cupular shape to a flatter or undulate (wavy) form. The disc of the apothecia ranges in colour from light yellow to brownish and may sometimes have black blotches or shading. The smooth excipulum , or the outer layer of the apothecia, encloses a thin margin that often becomes excluded, with only a few rays extending outward. [1]
Usnea pallidocarpa produces eight simple , ellipsoid, hyaline (translucent) ascospores per ascus (the spore-bearing structure). The photobiont – the photosynthesizing partner in the lichen symbiosis – is of the trebouxioid type. The secondary chemistry of Usnea pallidocarpa is characterised by an inconsistent presence of hypostrepsilic acid, as identified by thin-layer chromatography. [1]
Usnea pallidocarpa is known to occur only in a single location within the Argentinean Andean Cordillera in the southern part of South America. This lichen is an alpine species, growing at an elevation of about 1800 metres. It typically grows on rocks and is found in the company of other lichen species such as U. lambii , U. perpusilla , and U. sphacelata . [1]
Parmelia is a genus of medium to large foliose (leafy) lichens. It has a global distribution, extending from the Arctic to the Antarctic continent but concentrated in temperate regions. There are about 40 species in Parmelia. In recent decades, the once large genus Parmelia has been divided into a number of smaller genera according to thallus morphology and phylogenetic relatedness.
Ochrolechia is the sole genus in the fungal family Ochrolechiaceae. It comprises about 40 species of crustose lichens. These lichens typically form uneven, often thick, crust-like growths on various surfaces and are characterised by their white to pale grey thalli, which may have a greenish tint. The genus has a long evolutionary history, with fossils dating back to the Paleogene period, about 34 million years ago. Ochrolechia species have disc-like apothecia, which are usually yellowish or brownish-pink and often covered with a fine white powdery coating. The genus is widely distributed and includes both common and rare species, with some found in extreme environments such as arctic and alpine regions. Ochrolechia lichens produce diverse secondary metabolites, including orcinol depsides, depsidones, and xanthones.
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.
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.
Allantoparmelia is a genus of lichenised fungi in the large family Parmeliaceae. It is a genus of only three currently accepted species. All three Allantoparmelia lichens have a foliose growth form. They appear to be a very slow growing group of lichens, with a mean annual thallus diameter increase of only 0.23–0.35 mm per year.
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.
Himantormia is a genus of lichen-forming fungi in the family Parmeliaceae. It consists of two species found in the southernmost parts of South America and Antarctica. Both species are characterised by a paraplectenchymatous cortex composed of large, dark pigmented cells, a pachydermatous medulla, and the absence of lichenin in their cell walls. While morphologically similar in some aspects, the species can be distinguished by their lobe shapes, cortex cell sizes, medulla structure, and distinct secondary metabolite compositions, with H. deusta producing fumarprotocetraric acid as its major compound and H. lugubris containing alectorialic acid as its primary metabolite.
Hypotrachyna lueckingii is a species of corticolous (bark-dwelling), foliose lichen in the family Parmeliaceae. It is only known to occur at high elevations on the Cordillera de Talamanca in Costa Rica.
Dolichousnea is a genus of fruticose lichens in the family Parmeliaceae. It has three species. The widely distributed type species, Dolichousnea longissima, is found in boreal regions of Asia, Europe, and 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.
Usnea lambii is a small species of fruticose lichen in the family Parmeliaceae. It was first formally described as a new species in 1954 by Henry Imshaug. It has a bipolar distribution, that is, it occurs at both of Earth's polar regions. It is also found at high elevations in Mount Rainier National Park in Washington state, where it was first discovered.
Hypotrachyna constictovexans is a little-known species of foliose lichen in the family Parmeliaceae. Known only from a single specimen collected in 1976, it is found in the highlands of Peru. Its thallus can grow over 5 cm wide, featuring long, straight, and separate lobes that are highly convex and tube-like, with a pale grey, slightly shiny upper surface adorned with cylindrical isidia.
Menegazzia endocrocea is a species of foliose lichen in the family Parmeliaceae. It is found in Australia. The lichen forms irregular rosettes up to 10 cm wide with hollow, cylindrical lobes that branch dichotomously, featuring a pale grey to cream-grey upper surface with roundish holes and a wrinkled, black lower surface. It has scattered apothecia with a reddish-brown disc, two-spored asci, and abundant pycnidia, identified chemically by compounds like atranorin and stictic acid.
Thelotrema fijiense is a little-known species of corticolous (bark-dwelling), crustose lichen in the family Graphidaceae. It is known from Fiji.
Usnea galapagona is a species of beard lichen in the family Parmeliaceae. It is endemic to the Galápagos Islands. The lichen is easily recognized by its special structure. It has a tough, glass-like outer layer, a thick central core, and a very faint, almost invisible inner layer. This lichen stands upright and has a reddish colour near its base. Its branches split unevenly and are generally few in number, without any small, hair-like structures.
Nitidochapsa is a genus of lichen-forming fungi in the family Graphidaceae. It has five species of corticolous (bark-dwelling), crustose lichens.
Myriotrema frondosolucens is a species of corticolous (bark-dwelling) script lichen in the family Graphidaceae. It is found in Costa Rica.
Glaucotrema is a genus of lichen-forming fungi in the family Graphidaceae. It has five species.
Pseudotopeliopsis is a genus of lichen-forming fungi in the family Graphidaceae. It has two species.
Enigmotrema is a fungal genus in the family Graphidaceae. It contains only one known species, Enigmotrema rubrum, a lichen which was discovered in Costa Rica. Both the genus and species were first described in 2012 by the lichenologist Robert Lücking. The genus name combines the Greek words for "mystery" and "hole", referring to the unusual appearance of its reproductive structures. Enigmotrema is characterised by its olive-coloured body (thallus) and distinctive dark red fruiting bodies (apothecia) that undergo a unique opening process as they mature. The genus is closely related to Cruentotrema but differs in its genetic makeup and the development of its fruiting bodies. Currently, Enigmotrema is only known from a single location in a montane rainforest in Costa Rica, where it was found growing on tree bark.