View source for Draft:Description of Chaenotheca ferruginea

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'''''Chaenotheca'' ''ferruginea''''' is a fungus commonly known as '''Rusty Stubble Lichen'''.<ref name=":0">{{Cite web |title=Consortium of Lichen Herbaria - Chaenotheca ferruginea |url=https://lichenportal.org/portal/taxa/index.php?taxon=52574&clid=1118 |access-date=2024-11-06 |website=lichenportal.org}}</ref> '''''Chaenotheca'' ''ferruginea''''' is a lichenized fungus that grows on willow tree bark as well as other sources of wood. This lichen species was originally discovered in the United Kingdom. However, there have since been many observations across the world, including in the United States, Europe, and in Australia. This species was originally described within the genus ''Calicium'' but has since been placed into the genus ''Chaenotheca''.


== Taxonomy ==
{{Speciesbox
| image = Chaenotheca ferruginea a1(3).jpg
| image_caption = Chaenotheca ferruginea growing on wood.
| genus = Chaenotheca
| species = ferruginea
| authority = [[Theodor Magnus Fries|Th. M. Fries]] (1860)
| synonyms = ''Calicium ferrugineum'' <small>(Turner)</small>
''Cyphelium ferrugineum'' <small>(Ach.)</small>
''Phacotrum ferrugineum'' <small>(Gray)</small>
| synonyms_ref = 
}}

Given the appearance of this lichen, most common names that are used to describe ''Chaenotheca ferruginea'', including the Rusty Stubble Lichen, refer to the distinctive, stalked apothecia. These stalked apothecia notably protrude above the thallus of this lichen.

This lichen was first described in 1812 in the literature of [[English Botany]], edited and published by [[James Sowerby]].<ref>{{Cite book |last1=Sowerby |first1=James |url=https://www.biodiversitylibrary.org/bibliography/11893#/summary |title=English botany, or, Coloured figures of British plants |last2=Sowerby |first2=James |last3=Boswell |first3=John T. |last4=Lankester |first4=Phebe |last5=Lankester |first5=Phebe |last6=Salter |first6=John William |last7=Sowerby |first7=James de Carle |last8=Sowerby |first8=John E. |date=1863 |publisher=R. Hardwicke |edition=3rd ed., enl., re-arranged according to the natural orders, and entirely rev., with descriptions of all the species by the editor. |location=London}}</ref> This was within a much larger, comprehensive collection of illustrations and descriptions of various flora. The work contained multiple lichens, including those now considered in the genus ''Chaenotheca''.

Since the discovery of this organism, most ''Chaenotheca'' were referred to as part of the genus ''Calicium'', mainly due to the work of [[Erik Acharius]].<ref>{{Cite book |last=Acharius |first=Erik |title="Afhandling om de cryptogamiske vexter, som komma under namn af Calicioidea; Andra Stycket." |publisher=Kongliga vetenskaps academiens handlingar |year=1816 |edition=2nd |pages=260–291 |language=Swedish |trans-title=Thesis on the cryptogamic plants, which come under the name of Calicioidea; Second Edition.}}</ref><ref name=":1">{{Cite journal |last=Tibell |first=Leif |date= 2001|title=Photobiont Association and Molecular Phylogeny of the Lichen Genus Chaenotheca |url=http://www.bioone.org/doi/abs/10.1639/0007-2745%282001%29104%5B0191%3APAAMPO%5D2.0.CO%3B2 |journal=The Bryologist |language=en |volume=104 |issue=2 |pages=191–198 |doi=10.1639/0007-2745(2001)104[0191:PAAMPO]2.0.CO;2 |issn=0007-2745}}</ref> This genus was characterized by the presence of a [[calicoid]] thallus with stalked apothecia that produce simple, pigmented, spherical spores. Since this discovery, numerous species have been described.

However, later on the use of the genus ''Calicium'' to describe specimens that now belong to the genus ''Chaenotheca'' was seen as inaccurate. Theodor Magnus Fries described this genus and proposed the placement of 8 of the species that were previously identified in ''Calicium'' into the genus ''Chaenothecia''.<ref>{{Cite book |last=Fries |first=Theodor Magnus |title=Lichenes arctoi Europae Groenlandiaeque hactenus cogniti. |year=1860 |language=Latin}}</ref><ref name=":1" />

=== Etymology ===
The genus Chaenotheca can be split into Chaeno- and -theca. In Latin, Chaeno is based from Chaeto, which has the meaning of haired or bristled. Theca comes from Latin as well and has a meaning of encased or encapsulated.<ref>{{Cite web |title=thesaurus {{!}} Etymology of thesaurus by etymonline |url=https://www.etymonline.com/word/thesaurus |access-date=2024-11-06 |website=www.etymonline.com |language=en}}</ref>

=== Genetic Evaluation ===
In 2013, a genomic study was published discussing the phylogenetic placement of calicoid fungi,<ref name=":2">{{Cite journal |last1=Prieto |first1=Maria |last2=Baloch |first2=Elisabeth |last3=Tehler |first3=Anders |last4=Wedin |first4=Mats |date= 2013|title=Mazaedium evolution in the Ascomycota (Fungi) and the classification of mazaediate groups of formerly unclear relationship |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1096-0031.2012.00429.x |journal=Cladistics |language=en |volume=29 |issue=3 |pages=296–308 |doi=10.1111/j.1096-0031.2012.00429.x |issn=0748-3007}}</ref> which are those with a wart like thallus with regions above and below the substrate, including what is now Chaenotheca ''ferruginea''. This analysis discussed the placement of multiple Classes and Orders, including [[Coniocybaceae|Coniocybacae]]. This paper proposed the new Class and Order which is now [[Coniocybaceae|Coniocybomycetes]] and [[Coniocybales|Conioybales]] respectively.<ref name=":2" /> The genetic analysis of many lichens in the genus Chaenotheca were placed into this grouping as well. Another, more recent, phylogenetic analysis, conducted in 2023, focusing on the ITS region of the species within the genus Chaenotheca and its close relatives further showed the differences between some of the subgroups within Coniocybales.<ref>{{Cite journal |last1=Suija |first1=A. |last2=McMullin |first2=R.T. |last3=Lõhmus |first3=P. |date=2023-12-15 |title=A phylogenetic assessment of a fungicolous lineage in Coniocybomycetes: Chaenotricha, a new genus of Trichaptum-inhabiting species |url=https://www.ingentaconnect.com/content/wfbi/fuse/2023/00000012/00000001/art00014;jsessionid=2ahl5esjhvukp.x-ic-live-03 |journal=Fungal Systematics and Evolution |volume=12 |issue=1 |pages=255–270 |doi=10.3114/fuse.2023.12.13 |pmc=10918626 |pmid=38455956}}</ref>

== Characteristics ==

=== General Characteristics ===
[[File:Chaenotheca ferruginea 178725922.jpg|thumb|Stalked Apothecia of Chaenotheca ferruginea]]
The macroscopic appearance of this lichen is quite distinct. It is recognizable by the apparent wart-like thallus and very apparent stalked apothecia that are quite small and have a pin or needle-like appearance. The thallus of this lichen is typically a light gray, with patches of yellow or red-orange as well. The appearance is [[verrucose]], meaning that it has patches of thallus elevated above the substrate as well as growth beneath.<ref name=":0" /> This is what gives it the characteristic wart-like structure.

Additionally, the very distinct apothecial structures are typically a shiny black color with a lighter, sometimes orange top. These stalked structures tend to be 1 to 2 millimeters tall with a stalk width of between 0.07 and 0.15 millimeters.<ref name=":3">{{Cite web |title=Chaenotheca ferruginea |url=https://fungi.myspecies.info/all-fungi/chaenotheca-ferruginea |access-date=2024-11-06 |website=fungi.myspecies.info}}</ref> These structures are a key feature of those within the order Coniocybales. Additionally it is of note that the apothecia on these stalked structures are convex, whereas most are usually cup shaped.

The apothecia have a dusty cap, called the capitulum, which is the ascocarp of this organism. It is usually a light brown, but can also be yellow in appearance. This structure contains the ascospore mass and is the sexual structure of this organism.

=== Distinct Features ===
In addition to the very visual features associated with Chaenotheca ''ferruginea'' there are more features that cannot be seen by observation alone. This genus tends to have a sterile thallus, meaning that no asexual reproduction has been observed with this genus. Additionally, the tissue of the thallus contains a distinct yellow-red color and stains red under a [[Prussian blue stain|Prussian Blue]] stain,<ref name=":3" /> meaning that there is little to no ferrous iron present in the tissue. It has also been found that this lichen is resistant to environmental SO2.

=== Morphology ===
[[File:Chaenotheca ferruginea 4540 07 med.jpg|thumb|Spores visualized from a sample of Chaenotheca ''ferruginea'']]
The distinct convex apothecium contains groups of [[Ascus|asci]] bundled together alongside sterile hyphae that grow from the center of the stalk. These asci tend to be cylindrical in shape and contain 8 [[ascospores]] each. Additionally, the arrangement of these ascospores can be either in 1 or 2 rows, still coming to a total of 8 ascospores per asci.<ref name=":0" />
[[File:Chaenotheca ferruginea 4540 12 med.jpg|thumb|Cross sectional view of the apothecium of Chaenotheca ''ferruginea'']]
The spores of this organism are distinct in their shape and coloration. The ascospores of this fungus are globose, or spherical and have a distinct yellow-brown coloration. Another notable characteristic of these spores is that they are fissured in their structure. Under a microscope this appears as defined creases in the spore. However, this fissured feature is mainly observed in mature spores. These spores tend to be 7 to 8 micrometers in diameter as well.<ref name=":0" />

The [[photobiont]] that this fungus forms a lichenized structure alongside is typically of the genus [[Trebouxia]], which is a form of green algae.<ref name=":1" /> There are other genera that species in the Chaenotheca genus will form a lichen with, but still these are typically still other green algae. Trebouxia in particular is a green, globose algae that lives in conjunction with Chaenotheca ''ferruginea''.

== Ecology ==

=== Distribution ===
Chaenotheca ''ferruginea'' is widely distributed across Europe and is also somewhat prolific on the East and West coasts of the United States. However, there have been observations of this species globally, including in Costa Rica, Argentina, Australia, and New Zealand.<ref name=":0" />

=== Human Impact ===
This organism tends to grow on bark and other sources of wood including tree stumps and wood fences. It is very common in Europe so it could be considered to be a slight concern in terms of cosmetics, however it is very unlikely that this is a significant issue caused by this lichen. Additionally, since they are so prolific and are not heavily impacted by atmospheric SO2, the Conservation Designations for UK Taxa has labelled this species as not endangered or threatened.<ref>{{Cite web |title=Conservation Designations for UK Taxa {{!}} JNCC Resource Hub |url=https://hub.jncc.gov.uk/assets/478f7160-967b-4366-acdf-8941fd33850b |access-date=2024-11-06 |website=hub.jncc.gov.uk}}</ref>

== References ==
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