Xanthoria

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Xanthoria
Xanthoria parietina

Xanthoria parietina

Systematics
Subdivision : Real ascent mushrooms (Pezizomycotina)
Class : Lecanoromycetes
Subclass : Lecanoromycetidae
Order : Teloschistales
Family : Teloschistaceae
Genre : Xanthoria
Scientific name
Xanthoria
( Fr. ) Th. Fr. , 1860

Xanthoria is a genus of lichenized fungi ( lichens ) from the Teloschistaceae familyand belongs to the leaf lichens (lichens with folious thalli). The genus type is the common yellow lichen, Xanthoria parietina . The algae livingin symbiosis with the genus Xanthoria belong to the genus Trebouxia . Representatives of the genus are widespread in the northern hemisphere, Xanthoria parietina has also been carried off to the southern hemisphere by human influence. Xanthoria parietina , which is native to Germany, is also due to its high tolerance to harmful substances very common and visually striking, as it colonizes the bark of living trees even in cities and thus provides for strikingly yellow-colored branches.

description

Macroscopic features

The thalli are folios and grow in the form of horizontal to partially rising lobes or lobes along the substrate. The thallus margins are not connected to the substrate and have a cortex both above and below . They are attached to the substrate by hapters (individual, short strands that extend from the underside of the thallus). The thalli are strikingly bright yellow to orange in color and react with potassium hydroxide (potassium hydroxide solution) deep red due to a chemical reaction of the pigment parietin . Most species develop fruiting bodies in the form of apothecia (cup-shaped fruiting bodies) that are darker orange in color than the thallus. The apothecia are lecanoroid (also called zeorin), that is, the apothecia border consists of both the thallus and the excipulum of the fruiting body. The apothecia are thus covered on the outside by the thallus. The thallus of some species shows isidia on the top of the lobes . Pycnidia are sunk into the thallus and inconspicuous; B. in Xanthoria parietina .

Microscopic features

The asci are unique and each contain eight spores. The spores are noticeably thick-walled, yet colorless-hyaline, two-celled with a very wide septum and contain a very narrow lumen, which has the shape of a dumbbell, since it extends as a very thin, recognizable plasma strand through the pore of the septum and thus the two lumens of the Connects cells through this cord (polar diblastic or polarilocular spores). Conidia (the pycnidia) are ellipsoidal. The cortex is paraplectenchymatic or intricate prosoplectenchymatic. The hyphae of the upper cortex show conspicuous, crystalline deposits made up of the pigment parietin.

polar diblastic spore of Xanthoria parietina

Differentiation from other genera

The genus Xanthoria sensu lato is defined by the thalli, which are attached to the substrate only with hackers and whose lobes at the edge of the thallus are accordingly not connected to the substrate, the polar diblastic spores with a strikingly wide septum and the pigment parietin. However, this genus definition, established by classical morphology and anatomy, is not genetically confirmed. Some of the genera split off from Xanthoria sensu stricto cannot be delimited using classical methods at the moment. There are no morphological or anatomical differences in the current genus definitions of Xanthoria s. st. and Polycauliona . With the help of the sequencing of the barcoding region ITS (rDNA), however, the genera of the subfamily Xanthorioideae can all be easily separated and distinguished from one another.

species

Xanthoria aureola
Xanthoria calcicola

The genus Xanthoria consists of around 15 species in the current, polyphyletic sense. However, the number of species described is much higher at 161. Only species that have been genetically tested for Xanthoria s are listed below . st. counting.

Examples of outsourcing from the genus Xanthoria : The species referred to in many works as Xanthoria elegans is z. B. currently listed in the genus Rusavskia as Rusavskia elegans . The species, also very well known under the name Xanthoria polycarpa, is now in the genus Polycauliona as Polycauliona polycarpa .

Systematics

The genus Xanthoria is placed in the order Lecanorales , to which most of the lichenized mushrooms belong. Within the Teloschistaceae family, the genus is divided into its own subfamily Xanthorioideae along with some other genera such as B. Athallia , Austroplaca , Calogaya , Flavoplaca , Orientophila , Pachypeltis , Polycauliona or Rusavskia . The current genus definition on the expression of the thallus must be revised, since the genus Xanthoria is polyphyletic in the current sense .

distribution

The genus Xanthoria is widespread in the northern hemisphere. The distribution center with the highest diversity is in Europe and there in the Mediterranean region . Occurrences of Xanthoria parietina in the southern hemisphere are classified as presumably anthropogenic (caused by displacement).

ecology

Representatives of the genus Xanthoria colonize the bark and bark of living and dead trees and bushes as well as basic to pH-neutral rocks.

Importance to other organisms

The genus Xanthoria s. st. serves as a host for many species of lichen parasitic fungi .

literature

Individual evidence

  1. ^ A b V. Robert, G. Stegehuis, J. Stalpers et al .: Xanthoria. In: MycoBank. International Mycological Association, Westerdijk Fungal Biodiversity Institute, 2020, accessed April 7, 2020 .
  2. ↑ a b c d e f g h i Jennifer Fiorentino: The genus Xanthoria (Teloschistaceae, lichenised Ascomycota) in the Maltese Islands. In: The Central Mediterranean Naturalist , 2011, 5 (3-4), pp. 9-17 ( online ).
  3. ↑ a b c d e f g h i j k l m n o p q r Ulf Arup, Ulrik Søchting, Patrik Frödén: A new taxonomy of the family Teloschistaceae . In: Nordic Journal of Botany . tape 31 , no. 1 , February 2013, p. 016-083 , doi : 10.1111 / j.1756-1051.2013.00062.x .
  4. ↑ L. Silberstein L, BZ Siegel, SM Sigel, A. Mukhtar, M. Galun: Comparative studies on Xanthoria parietina, a pollution-resistant lichen and Ramalina duriaei, a sensitive species. I. Effects of air pollution of physiological processes . In: Lichenologist . tape 28 , 1998, pp. 355-365 .
  5. ↑ Mireia Giralt, Pier Luigi Nimis, Josef Poelt: Studies on some species of the lichen genus Xanthoria with isidiiform vegetative permanent spores . In: J. Hattori Bot. Lab. No. 74 , 1993, pp. 271-285 .
  6. ^ A b Paul Canon et al .: Xanthoria parientina. In: All Fungi. 2020, accessed on April 6, 2020 .
  7. ↑ CNALH - Rusavskia elegans. Retrieved April 6, 2020 .
  8. ↑ CNALH - Polycauliona polycarpa. Retrieved April 6, 2020 .
  9. ↑ a b Jolanta Miadlikowska, Frank Kauff, Filip Högnabba, Jeffrey C. Oliver, Katalin Molnár: A multigene phylogenetic synthesis for the class Lecanoromycetes (Ascomycota): 1307 fungi representing 1139 infrageneric taxa, 317 genera and 66 families . In: Molecular Phylogenetics and Evolution . tape 79 , October 2014, p. 132–168 , doi : 10.1016 / j.ympev.2014.04.003 .
  10. ↑ Andrei Tsurykau, Javier Etayo: Capronia suijae (Herpotrichiellaceae, eurotiomycetes), a new fungus on Xanthoria parietina from Belarus, with a key to the lichenicolous species growing on Xanthoria s. st. In: The Lichenologist . tape 49 , no. 1 , January 2017, ISSN  0024-2829 , p. 1-12 , doi : 10.1017 / S0024282916000530 .

Web links

Commons : Xanthoria  - collection of images, videos and audio files