Phaeophyscia

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Phaeophyscia
Phaeophyscia orbicularis
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Caliciales
Family: Physciaceae
Genus: Phaeophyscia
Moberg (1977)[1]
Type species
Phaeophyscia orbicularis
(Neck.) Moberg (1977)
Synonyms[2]
  • Physciella Essl. (1986)[3]

Phaeophyscia is a genus of lichen-forming fungi in the family Physciaceae.

Description[edit]

Genus Phaeophyscia encompasses a variety of lichen species, characterised by their leaf-like (foliose) structure that often extends in lobes, which can either be short or elongate and tend to lie flat against the substrate, resembling a loosely shrubby form in some instances. These lobes are typically less than 1.5 mm wide and have a range of colours from pale grey or greenish grey to dark brown, becoming dark green when moistened. The surface of these lichens is matte, not covered in a powdery coating (epruinose), and usually lacks spots (maculae) or fringe-like projections (cilia) along the edges. The underside is typically whitish or more commonly black, with matching, simple roots (rhizines) that may extend beyond the lobe tips, giving an appearance similar to cilia.[4]

Some Phaeophyscia species develop soredia or isidia, specialised structures (propagules) used for asexual reproduction. The upper and lower layers of the thallus (cortex) are composed of closely packed cells (pseudoparenchymatous), with the algal partner (photobiont) being trebouxioid–that is, from the green algal genus Trebouxia. The reproductive organs (ascomata) are cup-shaped structures (apothecia) found on the lichen's surface, usually encircled by rhizines at their base, with a brown to black disc that lacks a powdery covering. The rim surrounding the reproductive disc (thalline exciple) is smooth and occasionally lobed.[4]

Internally, the Phaeophyscia lichen has a brown upper layer (epithecium), with colourless internal layers (hymenium and hypothecium). The supporting filamentous structures (hamathecium) consist of slender, often branching paraphyses with club-shaped tips that are pale brown with a thin dark brown top. The spore-producing structures (asci) are approximately cylindrical to club-shaped, containing eight spores of the Lecanora-type. The spores themselves are brown, thick-walled, and divided by a single cross-wall (1-septate), resembling those found in the genus Physcia.[4]

Asexual reproductive structures (conidiomata) are in the form of pycnidia, embedded within the lichen and mostly colourless, except for a brown area around the opening (ostiole). The asexual spores (conidia) are ellipsoidal in shape. In terms of chemical composition, Phaeophyscia lichens do not react to a solution of potassium hydroxide (K–) on the cortex and medulla, indicating the absence of atranorin. However, some species contain yellow to orange-red pigments that turn purple with potassium hydroxide (K+), known as skyrin, or terpenoids.[4]

Ecologically, Phaeophyscia lichens favour nutrient-rich or enriched substrates in well-lit environments. They are distinguished from the closely related Hyperphyscia by their ellipsoidal, not thread-like, conidia, while Physcia species have rod-shaped (bacilliform) conidia.[4]

Species[edit]

Phaeophyscia hirtella
Phaeophyscia pusilloides

References[edit]

  1. ^ Moberg, R. (1977). "The lichen genus Physcia and allied genera in Fennoscandia". Symbolae Botanicae Upsalienses. 22 (1): 1–108 (see p. 29).
  2. ^ "Phaeophyscia Moberg 1977". MycoBank. International Mycological Association. Retrieved 2011-11-21.
  3. ^ Esslinger, Theodore L. (1986). "Studies in the lichen family Physciaceae. VII. The new genus Physciella". Mycologia. 78 (1): 92–97. doi:10.2307/3793382. JSTOR 3793382.
  4. ^ a b c d e Cannon, P.; Thüs, H.; Aptroot, A.; Coppins, B.; Orange, A.; Sanderson, N.; Simkin, J. (2022). Caliciales: Physciaceae, including the genera Anaptychia, Heterodermia, Hyperphyscia, Mischoblastia, Phaeophyscia, Physcia, Physciella, Physconia, Rinodina and Tornabea (PDF). Revisions of British and Irish Lichens. Vol. 24. p. 9.
  5. ^ a b c d e f g h i j k l m Esslinger, T.L. (1978). "Studies in the lichen family Physciaceae. II The genus Phaeophyscia in North America". Mycotaxon. 7 (2): 283–320.
  6. ^ a b Moberg, R. (1983). "The genus Phaeophyscia in East Africa". Nordic Journal of Botany. 3 (4): 509–516.
  7. ^ Aptroot, A.; Sipman, H. (1991). "New lichens and lichen records from New Guinea". Willdenowia. 20: 221–256.
  8. ^ Hu, G.R.; Chen, J.B. (2003). "The lichen family Physciaceae (Ascomycota) in China IV. A new species of Phaeophyscia". Mycosystema. 22 (4): 534–535.
  9. ^ Fayyaz, Iram; Afshan, Najam-ul-Sehar; Khalid, Abdul Nasir (2022). "Phaeophyscia kashmirensis sp. nov. (Lecanorales, Physciaceae) from Azad Jammu and Kashmir, Pakistan". The Lichenologist. 54 (6): 355–361. doi:10.1017/s0024282922000275.
  10. ^ Esslinger, T.L. (1978b). "Studies in the lichen family Physciaceae. III. A new species of Phaeophyscia from Hawaii". Mycologia. 70 (6): 1247–1249.
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