''Canoparmelia rarotongensis'' is a species of

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 ...

in the family

Parmeliaceae The Parmeliaceae is a large and diverse family of Lecanoromycetes. With over 2700 species in 71 genera, it is the largest family of lichen-forming fungi. The most speciose genera in the family are the well-known groups: '' Xanthoparmelia'' ( 822 ...

. Found in

Rarotonga Rarotonga is the largest and most populous of the Cook Islands. The island is volcanic, with an area of , and is home to almost 75% of the country's population, with 13,007 of a total population of 17,434. The Cook Islands' Parliament buildings a ...

(

Cook Islands ) , image_map = Cook Islands on the globe (small islands magnified) (Polynesia centered).svg , capital = Avarua , coordinates = , largest_city = Avarua , official_languages = , lan ...

), it was formally described as a new species in 2000 by Simone Louwhoff and John Elix. The

type specimen In biology, a type is a particular wiktionary:en:specimen, 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 a ...

was collected by the second author from the

Muri Lagoon The Muri Lagoon is a lagoon in the district of Ngatangiia on the eastern coast of Rarotonga in the Cook Islands. The lagoon is a significant tourist attraction and the largest tourism revenue earner in the Cook Islands, accounting for 25% of touris ...

(on the eastern coast of Rarotonga), where it was found growing on hibiscus along the foreshore. It is named for its type locality. The main physical characteristic that distinguishes it from others in its genus is its conspicuous

isidia An isidium is a vegetative reproductive structure present in some lichens. Isidia are outgrowths of the thallus surface, and are corticated (i.e., containing the outermost layer of the thallus), usually with a columnar structure, and consisting o ...

, which are consistently inflated and branched.

Description

This lichen has a moderately attached, thin and flexible

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 ...

that can grow up to wide. The are unevenly shaped and connected in the centre, but separate near the tips, measuring 2–4 mm wide. The edges of the lobes are smooth and occasionally wavy, appearing flat, without any . The top surface is a dusty grey-green colour, unevenly cracked in the centre with visible

, which are inflated and mostly branched, forming clusters that can be up to 0.5 mm wide and up to 0.8–1 mm high. The medulla is white, while the bottom surface is black and dull, with a narrow brown margin measuring up to 1 mm wide. The rhizines are black, not densely spread, and have a coarse and simple appearance. No apothecia or were observed. ''Canoparmelia rarotongensis'' produces atranorin, chloroatranorin in the and

lecanoric acid Lecanoric acid is a chemical produced by several species of lichen.ubChem - Lecanoric acid"> Lecanoric acid is classified as a polyphenol and a didepside and it functions as an antioxidant. The acid is named after the lichen ''Lecanora''. The acid ...

in the medulla as major lichen products, and trace amounts of

orsellinic acid Orsellinic acid, more specifically ''o''-orsellinic acid, is a phenolic acid. It is of importance in the biochemistry of lichens, from which it can be extracted. It is a common subunit of depsides. Chemistry It can be prepared by the oxi ...

, and orcinol. Before this species, lecanoric acid had not been reported to occur in the genus ''

Canoparmelia ''Canoparmelia'' is a genus of lichen-forming fungi in the family Parmeliaceae. The widespread genus contains about 35 species. ''Canoparmelia'', a segregate of the parmelioid lichen genus ''Pseudoparmelia'', was circumscribed by John Elix and M ...

''. The expected results of standard chemical spot tests are K+ (yellow) in the cortex, and K−, C+ (red), PD− in the medulla.

References

{{Taxonbar, from=Q10441779 Parmeliaceae Lichen species Lichens described in 2000 Taxa named by John Alan Elix Lichens of the Pacific