Dictyonema Thelephora

''Dictyonema'' is a genus of mainly tropical basidiolichens in the family Hygrophoraceae.

The ''Dictyonema'' symbiosis

Most lichens are a symbiosis between an ascomycete fungus and a photosynthetic green alga. However, a small percentage of lichens (approximately 10%) are cyanolichens and contain a photosynthetic cyanobacterium instead of green algae, and an even smaller number (less than 1%) are basidiolichens and contain a basidiomycete fungus instead of an ascomycete. 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 Adgardh and Carl Kunth after examining a novel fungus that was sent to them from Brazil.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. 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''. This resulted in a rather diverse group of lichens that has since grown in size to more than 20 species. There is, however, some recent debate over whether or not all of these species should be included in the same genus.

Species

A recent (2020) estimate placed 28 species in ''Dictyonema''.
*''Dictyonema aeruginosulum''
*''Dictyonema album'' – Africa
*''Dictyonema applanatum'' – Bolivia
*''Dictyonema barbatum'' – Galápagos Islands
*''Dictyonema caespitosum''
*''Dictyonema coppinsii'' – Europe
*''Dictyonema darwinianum'' – Galápagos Islands
*''Dictyonema diducens''
*''Dictyonema discocarpum'' – Bolivia
*''Dictyonema giganteum''
*''Dictyonema gomezianum''
*''Dictyonema guadalupense''
*''Dictyonema hapteriferum'' – Bolivia
*''Dictyonema hernandezii''
*'' Dictyonema huaorani''
*'' Dictyonema irpicinum''
*'' Dictyonema irrigatum''
*''Dictyonema krogiae'' – Africa
*'' Dictyonema lawreyi''
*'' Dictyonema ligulatum''
*'' Dictyonema metallicum''
*'' Dictyonema moorei''
*'' Dictyonema obscuratum''
*''Dictyonema pectinatum'' – Galápagos Islands
*'' Dictyonema phyllophilum''
*'' Dictyonema ramificans'' – Galápagos Islands
*'' Dictyonema reticulatum''
*'' Dictyonema scabridum''
*'' Dictyonema subobscuratum'' – Galápagos Islands
*'' Dictyonema thelephora''
*'' Dictyonema tricolor'' – Africa
*'' Dictyonema yunnanum''

Morphology and ecology

''Dictyonema'' is a diverse group of lichens. There are species of a variety of different shapes, including foliose, crustose, and filamentous. Most species grow on soil, rock, moss, or rotting logs, but one species grows on the leaves of trees. Although species of ''Dictyonema'' are mainly tropical, they range from the tropical lowlands to an elevation of in the Andes.

Evolutionary relationships and lichenization

The ''Dictyonema'' fungus is a basidiomycete, so it developed lichen lichens. Within the basidiomycetes, ''Dictyonema'' is closely related to three other genera of basidiolichens that are also in the family Hygrophoraceae: '' Lichenomphalia'', ''Acantholichen'', and '' Cyphellostereum''. 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. 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. It is not yet understood why these fungi are more inclined to become lichens.

Traditional use

An unidentified species of ''Dictyonema'', possibly '' Dictyonema sericeum'', is called ''nenendape'' by the Huaorani people of Amazon jungle of Ecuador. An infusion is made with this lichen that causes intense hallucinations due to high contents in both dimethyltryptamine and psilocybin, and it is used by the shaman to call upon malevolent spirits to curse people. It is also used to cause sterility.

See also

* List of Agaricales genera

References

*

{{Taxonbar, from=Q3023415

Lichen genera
Agaricales genera
Basidiolichens
Taxa described in 1822