Cladia

Cladia was circumscribed by Finnish lichenologist William Nylander in 1870 with Cladia aggregata as the type species.[3] Rex Filson created a separate family, the Cladiaceae, to contain the genus,[4] but this is no longer used and the genus is classified in the family Cladoniaceae.[5] An updated phylogeny of the Cladoniaceae was published in 2018.[6]

Molecular phylogenetic evidence showed that the genera Heterodea and Ramalinora were nested within Cladina,[7][8] so they are now synonyms. Because the name Heterodea predated Cladina, the generic name Cladia was proposed for conservation against Heterodea to avoid several nomenclatural changes that would have been necessary.[9][10] The proposal was accepted by both the Nomenclature Committee for Fungi and the General Committee.[11][12]

Cladia consists of fruticose lichens with typically a perforate pseudopodetia with a external cartilaginous layer. The apothecia are black or brown and have a persistent proper margin and a flat disc. The asci are eight-spored with a well-developed amyloid tholus with a darker-staining central tube. The pycnidia are immersed in grossly black to brown projections that are initially blunt and measure up to 0.5 mm long and eventually become needle-like and up to 1 mm long.[13]

Eight species of lichenicolous fungi are known to grow on Cladia:[14] Echinothecium cladoniae Keissl. nom. nud. (on C. aggregata from Columbia; Etayo 2002), Lichenoconium echinosporum D. Hawksw. (on C. muelleri from Australia; Hawksworth 1977), Roselliniella heterodeae Matzer & Hafellner (on C. muelleri from Australia; Matzer & Hafellner 1990); Pyrenidium actinellum Nyl. agg. (on C. aggregata from Columbia; Etayo 2002); Endococcus cladiae Zhurb. & Pino-Bodas; Lichenopeltella soiliae Zhurb. & Pino-Bodas, and Lichenosticta hoegnabbae Zhurb. & Pino-Bodas.

The type species, Cladia aggregata, is highly variable morphologically and has extensive chemical variation.[15] Kantvilas & Elix (1999) revised the C. aggregata complex in Tasmania and identified six chemotypes in C. aggregata sensu stricto.[13] Similarly, five chemotypes were found in specimens from the states of Paraná and Santa Catarina, Brazil. In both studies, most of them contained barbatic acid and 4-O-demethylbarbatic acid.[16] Barbatic acid is cytotoxic, and kills the worms of Schistosoma mansoni in in vitro studies. This is the causative agent of Schistosomiasis.[17]

Revisions of Cladia published in 2012 and 2013 included 23 species in the genus.[18][19] As of December 2020, Species Fungorum accepts 20 species in Cladia:[20]

• Cladia aggregata (Sw.) Nyl. (1870)
• Cladia beaugleholei (Filson) Parnmen & Lumbsch (2011)[18]
• Cladia blanchonii Parnmen & Lumbsch (2013)[18]
• Cladia cryptica Parnmen & Lumbsch (2013)[18]
• Cladia deformis Kantvilas & Elix (2000)[13]
• Cladia dumicola Kantvilas & Elix (2000)[13]
• Cladia glaucolivida (Müll.Arg.) Parnmen & Lumbsch (2012)[18]
• Cladia globosa Ahti (2000)[15]
• Cladia gorgonea (Eschw.) Parnmen & Lumbsch (2013)
• Cladia inflata (F.Wilson) D.J.Galloway (1977)
• Cladia moniliformis Kantvilas & Elix (1987)[21]
• Cladia muelleri (Hampe) Parnmen, Elix & Lumbsch (2012)[18]
• Cladia mutabilis Kantvilas & Elix (2000)[13]
• Cladia neocaledonica (Räsänen) Parnmen & Lumbsch (2013)
• Cladia occulta Kantvilas (2012)[22] – Tasmania
• Cladia oreophila Kantvilas & Elix (2000)[13]
• Cladia schizopora (Nyl.) Nyl. (1888)
• Cladia tasmanica Parnmen & Lumbsch (2013)[18]
• Cladia terebrata (Laurer) Parnmen & Lumbsch (2013)
• Cladia xanthocarpa Elix & P.M.McCarthy (2018)[23] – Australia