| 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 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.
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 compounds. Melanohalea was circumscribed in 2004 as a segregate of the morphologically similar genus Melanelia.
Melanelixia is a genus of foliose lichens in the family Parmeliaceae. It contains 15 Northern Hemisphere species that grow on bark or on wood. The genus is characterized by a pored or fenestrate epicortex, and the production of lecanoric acid as the primary chemical constituent of the medulla. Melanelixia was circumscribed in 2004 as a segregate of the related genus Melanelia.
Menegazzia is a genus of lichenized fungi containing roughly 70 accepted species. The group is sometimes referred to as the tree flutes, honeycombed lichens, or hole-punch lichens. The most obvious morphological feature of the genus is the distinctive perforations spread across the upper side of the thallus. This makes the group easy to recognise, even for those not particularly familiar with lichen identification.
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.
Calopadia editiae is a species of lichen in the family Pilocarpaceae. It is found in Tanzania, with a distribution that extends to Costa Rica and the Galápagos Islands. It can be found on leaves or bark and is characterised by its pale grey to brownish grey colour, rounded apothecia and distinctive pruina. Described as new to science in 2011, the species was named in honour of Hungarian lichenologist Edit Farkas.
Lichens are symbiotic organisms made up of multiple species: a fungus, one or more photobionts and sometimes a yeast. They are regularly grouped by their external appearance – a characteristic known as their growth form. This form, which is based on the appearance of vegetative part of the lichen, varies depending on the species and the environmental conditions it faces. Those who study lichens (lichenologists) have described a dozen of these forms: areolate, byssoid, calicioid, cladoniform, crustose, filamentous, foliose, fruticose, gelatinous, leprose, placoidioid and squamulose. Traditionally, crustose (flat), foliose (leafy) and fruticose (shrubby) are considered to be the three main forms. In addition to these more formalised, traditional growth types, there are a handful of informal types named for their resemblance to the lichens of specific genera. These include alectorioid, catapyrenioid, cetrarioid, hypogymnioid, parmelioid and usneoid.
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.
Aspiciliopsis is a genus of lichen-forming fungi in the family Trapeliaceae. It has two species, both of which occur in the Southern Hemisphere.
Usnea sphacelata is a species of saxicolous (rock-dwelling), fruticose lichen in the large family Parmeliaceae. It is found in both polar regions of Earth, as well as in southern and northern South America and in New Zealand.
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.
Lecidea lygommella is a species of saxicolous (rock-dwelling), crustose lichen in the family Lecideaceae. It spreads up to 7 cm wide with a thin thallus varying in colour from whitish and pale grey to rusty red-brown, featuring areolate surfaces with irregularly shaped areoles. Its fruiting bodies range from slightly embedded to sitting atop the thallus and black, flat to slightly convex apothecial discs. Unlike its lookalike Lecidea lygomma, L. lygommella does not produce any secondary chemicals. It is found in New South Wales and Victoria, Australia, where it grows on rocks in alpine areas.
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.
Hypogymnia amplexa is a species of corticolous (bark-dwelling), foliose lichen in the family Parmeliaceae. It is found in the western United States and Canada.
Thelotrema fijiense is a little-known species of corticolous (bark-dwelling), crustose lichen in the family Graphidaceae. It is known from Fiji.
Ocellularia vizcayensis is a rare species of corticolous (bark-dwelling) lichen in the family Graphidaceae. It is known from a single collection made in Luzon, Philippines. The lichen thallus is a white, irregularly structured, areolate surface with a layer that includes a photosynthetic partner, both containing large calcium oxalate crystals. Its fruiting bodies are either embedded or protruding, round, with very narrow openings, and contain large, oblong, colorless spores that turn violet-blue when stained with iodine.
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.