Psoroma

<i>Psoroma</i>

Psoroma

Genus of lichen-forming fungi

Psoroma is a genus of lichen-forming fungi in the family Pannariaceae. The widespread genus contains about 30 species,[4] most of which are found in south temperate regions.[5]

Quick Facts Psoroma, Scientific classification ...

Taxonomy

The genus was circumscribed by the French botanist André Michaux in 1803.[6]

Some species formerly in Psoroma were transferred to the new genera Psorophorus and Xanthopsoroma in 2010.[7] The genus Joergensenia was erected in 2008 to contain the species formerly known as Psoroma cephalodinum.[8]

Description

The genus Psoroma is characterised by its small scale-like thallus, with an underlying layer that is barely noticeable. It houses a green algal photobiont, possibly the algae Myrmecia, which collaborates with the fungus to perform photosynthesis. Psoroma species have cephalodia, structures containing the cyanobacterium Nostoc.[9]

The reproductive organs, known as ascomata, are apothecial in form—essentially sessile and somewhat cup-shaped with a raised, enduring edge. Within these structures, the supporting filaments, or paraphyses, may be simple or branch towards their tips, which do not expand or form a cap, staining a dusky blue when iodine is applied. The spore-producing asci are elongated, either club-shaped or cylindrical, featuring a distinctive structure at their tips where a central tube stains blue with iodine within a lighter-staining area, surrounded by a clear amyloid ring.[9]

Spores produced by Psoroma are single-celled, colourless, and often contain one or two large oil droplets. Their shape is ellipsoidal, with a surface that is warty or ridged, and somewhat pointed at the ends. For asexual reproduction, Psoroma develops pycnidia, which are pale brown, and produces simple, rod-shaped, colourless conidia.[9]

Chemically, Psoroma usually lacks detectable secondary metabolites (lichen products) through thin-layer chromatography, although in rare cases, porphyrilic acid and related compounds may be present.[9]

Species

As of March 2024, Species Fungorum (in the Catalogue of Life) accepts 28 species of Psoroma.[4]

Psoroma sphinctrinum
  • Psoroma absconditum Øvstedal (2008)[10]
  • Psoroma antarcticum S.G.Hong & Elvebakk (2018)[11] – Antarctica
  • Psoroma asperellum Nyl. (1869)
  • Psoroma caliginosum Stirt. (1877)
  • Psoroma capense Elvebakk, S.G.Hong & Rämä (2020) – South Africa[12]
  • Psoroma cinnamomeum Malme (1925)
  • Psoroma cyanosorediatum P.M.Jørg. (2004)
  • Psoroma dichroum (Hook.f. & Taylor) P.M.Jørg. (2014)
  • Psoroma echinaceum P.M.Jørg. & Wedin (1999)[13]
  • Psoroma esterhuyseniae Elvebakk (2020) – South Africa[12]
  • Psoroma filicicola P.M.Jørg. & Sipman (2006)
  • Psoroma fruticulosum P.James & Henssen (1983)[14]
  • Psoroma geminatum P.M.Jørg. (1999)[13]
  • Psoroma hirsutulum Nyl. ex Cromb. (1875)
  • Psoroma hypnorum (Vahl) Gray (1821)[15]
  • Psoroma inflatum Elvebakk (2021)[16] – New Zealand
  • Psoroma macquariense C.W.Dodge (1970)[17] – Antarctica
  • Psoroma macrosporum (P.M.Jørg. & Palice) P.M.Jørg. (2014)
  • Psoroma multifidum P.M.Jørg. (2004)[15]
  • Psoroma nigropunctatum Elvebakk & Elix (2021)[18] – Australia
  • Psoroma nivale Fryday, Elvebakk, F.L.Anderson & J.Gagnon (2019)[19] – Quebec, Canada
  • Psoroma obscurius (Nyl.) P.M.Jørg. (2014)
  • Psoroma orphninum (Hue) P.M.Jørg. (2014)
  • Psoroma paleaceum (Fr.) Nyl. (1855)
  • Psoroma pholidotoides (Nyl.) Trevis. (1869)
  • Psoroma polychidioides (Zahlbr.) P.M.Jørg. (2014)
  • Psoroma saccharatum Scutari & Calvelo (1995)[20] – Argentina
  • Psoroma sphinctrinum (Mont.) Nyl. (1855)
  • Psoroma xanthorioides (P.M.Jørg.) P.M.Jørg. (2014)
  • Psoromaria rosulata (P.M.Jørg. & D.J.Galloway) P.M.Jørg. & H.L.Andersen (2015)
  • Psoromaria versicolor (Müll.Arg.) P.M.Jørg. & H.L.Andersen (2015)

References

  1. [1]
    "Psoroma Ach. ex Michx. 1803". MycoBank. International Mycological Association. Retrieved 2012-02-25.
  2. [2]
    Zahlbruckner, A. (1941). "Lichenes Novae-Zelandiae a cl H. H. Allan eiusque collaboratoribus lecti". Denkschriften der Akademie der Wissenschaften (Wien), Math.-nat. Kl. (in German). 104: 249–380 [275].
  3. [3]
    Ciferri, R.; Tomaselli, R. (1953). "Saggio di una sistematica micolichenologica". Atti dell'Istituto Botanico della Università e Laboratorio Crittogamico di Pavia (in Italian). 10 (1): 25–84.
  4. [4]
    "Psoroma". Catalogue of Life. Species 2000: Leiden, the Netherlands. Retrieved 31 March 2024.
  5. [5]
    Kirk, P.M.; Cannon, P.F.; Minter, D.W.; Stalpers, J.A. (2008). Dictionary of the Fungi (10th ed.). Wallingford, UK: CAB International. p. 575. ISBN 978-0-85199-826-8.
  6. [6]
    Michaux, A. (1803). Flora Boreali-Americana (in Latin). Vol. 2. p. 321.
  7. [7]
    Elvebaak, A.; Robertsen, E.H.; Park, C.H.; Hong, S.G. (2010). "Psorophorus and Xanthopsoroma, two new genera for yellow-green, corticolous and squamulose lichen species, previously in Psoroma". The Lichenologist. 42 (5): 563–585. doi:10.1017/S0024282910000083.
  8. [8]
    Passo, A.; Stenroos, S.; Calvelo, S. (2008). "Joergensenia, a new genus to accommodate Psoroma cephalodinum (lichenized Ascomycota)". Mycological Research. 112 (12): 1465–1474. doi:10.1016/j.mycres.2008.06.025. PMID 18675347.
  9. [9]
    Cannon, P.; Aptroot, A.; Coppins, B.; Sanderson, N.; Simkin, J. (2021). Peltigerales: Pannariaceae, including the genera Fuscopannaria, Leptogidium, Nevesia, Pannaria, Parmeliella, Pectenia, Protopannaria and Psoroma (PDF). Revisions of British and Irish Lichens. Vol. 9. p. 14.Open access icon
  10. [10]
    Øvstedal, D.O.; Gremmen, N.J.M. (2008). "Additions and corrections to the lichens of Heard Island". The Lichenologist. 40 (3): 233–242. doi:10.1017/S002428290800741X.
  11. [11]
    Park, Chae Haeng; Hong, Soon Gyu; Elvebakk, Arve (2018). "Psoroma antarcticum, a new lichen species from Antarctica and neighbouring areas". Polar Biology. 41: 1083–1090. doi:10.1007/s00300-018-2265-x.
  12. [12]
    Elvebakk, Arve; Hong, Soon Gyu; Park, Chae Haeng; Rämä, Teppo (2020). "Psoroma capense and P. esterhuyseniae (Pannariaceae), two new alpine species from South Africa". The Lichenologist. 52 (5): 345–352. doi:10.1017/S0024282920000377. hdl:10037/20103.
  13. [13]
    Jørgensen, P.M.; Wedin, M. (1999). "On Psoroma species from the Southern Hemisphere with cephalodia producing vegetative dispersal units". Lichenologist. 31 (4): 341–347. doi:10.1017/S0024282999000456.
  14. [14]
    Henssen, A.; Renner, B.; Marton, K.; James, P.W.; Galloway, D.J. (1983). "Studies in the lichen genus Psoroma 2. Psoroma fruticulosum and Psoroma rubromarginatum". Mycotaxon. 18 (1): 29–48.
  15. [15]
    Jørgensen, P.M. (2004). "Further contributions to the Pannariaceae (lichenized Ascomycetes) of the Southern Hemisphere". Bibliotheca Lichenologica. 88: 229–253.
  16. [16]
    Elvebakk, Arve (2021). "Psoroma inflatum, a new alpine lichen from New Zealand" (PDF). Australasian Lichenology. 89: 49–53.
  17. [17]
    Dodge, C.W. (1970). "Lichenological notes on the flora of the Antarctic Continent and the Subantarctic islands. IX-XI". Nova Hedwigia. 19 (3–4): 439–502.
  18. [18]
    Elvebakk, Arve; Elix, John A. (2021). "Psoroma nigropunctatum sp. nov., an alpine lichen in south-eastern Australia related to P. buchananii" (PDF). Australasian Lichenology. 89: 54–61.
  19. [19]
    Fryday, Alan M.; Elvebakk, Arve; Anderson, Frances L.; Gagnon, Jean Y. (2019). "Psoroma nivale (Pannariaceae, lichenized Ascomycota) a new species with dark, elongate squamules and bacilliform ascospores from arctic Québec, Canada". The Lichenologist. 51 (5): 419–429. doi:10.1017/S0024282919000288. hdl:10037/18052.
  20. [20]
    Scutari, N.C.; Calavelo, S. (1995). "A new species of Psoroma (pannariaceae, lichenized Ascomycotina) from Tierra del Fuego, Argentina". Annales Botanici Fennici. 32 (1): 5–61 [56].
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