''Dictyonema'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of mainly tropical

basidiolichen Basidiolichens are lichenized members of the Basidiomycota, a much smaller group of lichens than the far more common ascolichens in the Ascomycota. In arctic, alpine, and temperate forests, the most common basidiolichens are in the agaric genus ...

s in the family

Hygrophoraceae The Hygrophoraceae are a family of fungi in the order Agaricales. Originally conceived as containing white-spored, thick-gilled agarics (gilled mushrooms), including '' Hygrophorus'' and ''Hygrocybe'' species (the waxcaps or waxy caps), DNA evi ...

The ''Dictyonema'' symbiosis

Most lichens are a symbiosis between an ascomycete

fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from t ...

and a photosynthetic

green alga The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...

. However, a small percentage of lichens (approximately 10%) are

cyanolichen Cyanolichens are lichens that apart from the basic fungal component ("mycobiont"), contain cyanobacteria, otherwise known as blue-green algae, as the photosynthesizing component ("photobiont"). Overall, about a third of lichen photobionts are cyan ...

s and contain a photosynthetic

cyanobacterium Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...

instead of green algae, and an even smaller number (less than 1%) are

s and contain a

basidiomycete Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Ba ...

fungus instead of an ascomycete. This makes ''Dictyonema'' more closely related to

mushroom A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is ...

s 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 Erast Parmasto (28 October 1928 – 24 April 2012) was a noted Estonian mycologist, bioscientist and botanist and onetime director of the Estonian Institute of Zoology and Botany. Parmasto was born in Nõmme. He became a member of the Estonian I ...

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 The Galápagos Islands (Spanish: , , ) are an archipelago of volcanic islands. They are distributed on each side of the equator in the Pacific Ocean, surrounding the centre of the Western Hemisphere, and are part of the Republic of Ecuador ...

Morphology and ecology

''Dictyonema'' is a diverse group of lichens. There are species of a variety of different shapes, including

foliose Foliose lichen is one of the morphological classes of lichens, which are complex organisms that arise from the symbiotic relationship between fungi and a photosynthetic partner, typically algae. This partnership allows lichen to live in diverse ...

crustose Crustose is a habit of some types of algae and lichens in which the organism grows tightly appressed to a substrate, forming a biological layer. ''Crustose'' adheres very closely to the substrates at all points. ''Crustose'' is found on rocks ...

, 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

, so it developed lichenization independently from the ascomycete lichens. Within the basidiomycetes, ''Dictyonema'' is closely related to three other genera of basidiolichens that are also in the family

: ''

Lichenomphalia ''Lichenomphalia'' is both a basidiolichen and an agaric genus. Most of the species have inconspicuous lichenized thalli that consist of scattered, small, loose, nearly microscopic green balls or foliose small flakes containing single-celled gr ...

'', '' 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 Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi ( ...

(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 The Huaorani, Waorani, or Waodani, also known as the Waos, are an Indigenous people from the Amazonian Region of Ecuador ( Napo, Orellana, and Pastaza Provinces) who have marked differences from other ethnic groups from Ecuador. The alternate ...

people of

Amazon jungle The Amazon rainforest, Amazon jungle or ; es, Selva amazónica, , or usually ; french: Forêt amazonienne; nl, Amazoneregenwoud. In English, the names are sometimes capitalized further, as Amazon Rainforest, Amazon Forest, or Amazon Jungle. ...

of Ecuador. An

infusion Infusion is the process of extracting chemical compounds or flavors from plant material in a solvent such as water, oil or alcohol, by allowing the material to remain suspended in the solvent over time (a process often called steeping). An in ...

is made with this lichen that causes intense

hallucination A hallucination is a perception in the absence of an external stimulus that has the qualities of a real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space. Hallucination is a combinati ...

s due to high contents in both

dimethyltryptamine ''N'',''N''-Dimethyltryptamine (DMT or ''N'',''N''-DMT, SPL026) is a substituted tryptamine that occurs in many plants and animals, including human beings, and which is both a derivative and a structural analog of tryptamine. It is used as a ...

and

psilocybin Psilocybin ( , ) is a naturally occurring psychedelic prodrug compound produced by more than 200 species of fungi. The most potent are members of the genus ''Psilocybe'', such as '' P. azurescens'', '' P. semilanceata'', and '' P.&nbs ...

, and it is used by the

shaman Shamanism is a religious practice that involves a practitioner (shaman) interacting with what they believe to be a spirit world through altered states of consciousness, such as trance. The goal of this is usually to direct spirits or spir ...

to call upon malevolent spirits to curse people. It is also used to cause sterility.

References

* {{Taxonbar, from=Q3023415 Lichen genera Agaricales genera Basidiolichens Taxa described in 1822