''Dendriscocaulon'' is a taxonomic name that has been used for a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
fruticose
A fruticose lichen is a form of lichen fungi that is characterized by a coral-like shrubby or bushy growth structure. It is formed from a symbiotic relationship of a photobiont such as green algae or less commonly cyanobacteria and one, two or mor ...
lichen
A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.cyanobacteria
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 ...
as the
photobiont
A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.taxonomic synonym of the genus '' Sticta'', a
foliose lichen
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 ...
(leafy form lichen), which generally has a
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 ...
as the photobiont partner.Form and structure - Sticta and 'Dendriscocaulon', Australian Botanic Garden website /ref> Lichens that have been called ''Dendriscocaulon'' or ''Sticta'' involve the same fungal species. They show dramatically different
morphology
Morphology, from the Greek and meaning "study of shape", may refer to:
Disciplines
*Morphology (archaeology), study of the shapes or forms of artifacts
*Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...
, may grow side-by-side, and mixed forms exist where different algae are growing within different portions of the same fungal
thallus
Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms wer ...
. The biochemistry of the two forms is very different, but the DNA sequences from the fungus and the photobiont can be distinguished using different primers for
DNA sequencing
DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...
.
Use of the name
Taxonomists now write the genus name with
scare quotes
Scare quotes (also called shudder quotes,Pinker, Steven. ''The Sense of Style: The Thinking Person's Guide to Writing in the 21st Century''. Penguin (2014) sneer quotes, and quibble marks) are quotation marks that writers place around a word o ...
around it, to make clear that they are not accepting the name as correct. The name can be convenient, however, because of the visible morphological difference, and because it was used in older literature.
The International Code of Botanical Nomenclature states that "For nomenclatural purposes names given to lichens apply to their fungal component." Article 13(d) Names of genera and species are based on
type specimens
In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes t ...
. The type of ''Dendriscocaulon'' Nyl. from New Zealand, published in 1888, is not the same as the type of '' Sticta'' (Schreb.) Ach., published in 1803. The fungal partner in the type specimen of ''Dendriscocaulon'' is therefore unlikely to be the same strain as the fungal partner in the type specimen of ''Sticta'', which raises the possibility that at some future time the two genera may be separated once more on the basis of genetic difference in the fungal partner, rather than by the photobiont or the morphology of the lichen. As with all lichens, the convention of nomenclature provides only partial illumination about the concepts of genus and species as they apply to the association of two or more species that are known as lichens.