Dictyonema

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Dictyonema
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Hygrophoraceae
Genus: Dictyonema
Kunth
(1822)
Type species
C.Agardh
(1822)

Dictyonema is a genus of mainly tropical basidiolichens in the family Hygrophoraceae.[1]

The Dictyonema symbiosis

Most lichens are a

cyanobacterium instead of green algae,[2] and an even smaller number (less than 1%) are basidiolichens and contain a basidiomycete fungus instead of an ascomycete.[3] This makes Dictyonema more closely related to mushrooms
than it is to most other lichens.

Taxonomy and naming

The genus Dictyonema was first named in 1822 by Carl Agardh and Carl Kunth after examining a novel fungus that was sent to them from Brazil.[4] The genus was redefined in 1978 when Erast Parmasto assessed 40 different species of basidiolichens that were previously divided into 3 families and 8 genera (including Cora, Dichonema, Laudatea, Rhipidonema, and Thelephora), and reduced them to 5 species in the single genus Dictyonema.[5] This resulted in a rather diverse group of lichens that has since grown in size to more than 20 species.[3] There is, however, some recent debate over whether or not all of these species should be included in the same genus.[6]

Species

A recent (2020) estimate placed 28 species in Dictyonema.[7]

Morphology and ecology

Dictyonema is a diverse group of lichens. There are species of a variety of different shapes, including foliose, crustose, and filamentous.[3] Most species grow on soil, rock,[15] moss,[16] or rotting logs,[17] but one species grows on the leaves of trees.[3] Although species of Dictyonema are mainly tropical, they range from the tropical lowlands to an elevation of 4,300 m (14,100 ft) in the Andes.[15]

Evolutionary relationships and lichenization

The Dictyonema fungus is a basidiomycete, so it developed lichenization independently from the ascomycete lichens.[18] Within the basidiomycetes, Dictyonema is closely related to three other genera of basidiolichens that are also in the family Hygrophoraceae: Lichenomphalia, Acantholichen, and Cyphellostereum.[3] The molecular data indicates that lichenization has evolved independently at least twice, and perhaps three times, within these four genera, which suggests that for some reason the fungi in Hygrophoraceae are predisposed to evolve into lichens.[3] The majority of the other, non-lichenized fungi in this family are saprotrophic (consuming decaying organic matter) or ectomycorrhizal (symbiotic with plant roots), although numerous species, such as Arrhenia, grow on mosses and derive nutrition from them.[3][19] It is not yet understood why these fungi are more inclined to become lichens.[3]

Traditional use

An unidentified species of Dictyonema, possibly

shaman to call upon malevolent spirits to curse people. It is also used to cause sterility.[20]

See also

References

  1. PMID 21628162
    .
  2. ^ Hawksworth, DL, PM Kirk, BC Sutton, and DN Pegler. 1995. Dictionary of the fungi. CAB, Wallingford
  3. ^
    PMID 19646529
    .
  4. ^ Kunth, CS, and CA Agardh. 1822. Synopsis Plantarum, Quas in Itinere ad Plagam Aequinoctialem Orbis Novi, Collegerunt Al. de Humboldt et Am. Bonpland (Paris). Volume 1, pg. 1.
  5. ^ Parmasto, E. (1978). "The genus Dictyonema ('Thelephorolichenes')". Nova Hedwigia. 29: 99–144.
  6. S2CID 85409631
    .
  7. .
  8. ^ .
  9. ^ a b c Lücking, Robert; Dal-Forno, Manuela; Wilk, Karina; Lawrey, James D. (2013). "Three new species of Dictyonema (lichenized Basidiomycota: Hygrophoraceae) from Bolivia". Acta Nova. 6: 4–16.
  10. ^
    S2CID 32287424
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