Roccella albida
Species of lichen From Wikipedia, the free encyclopedia
Species of lichen From Wikipedia, the free encyclopedia
Roccella albida is a species of saxicolous (rock-dwelling), fruticose lichen in the family Roccellaceae.[1] It is found on the Galápagos Islands. The lichen is characterised by its distinctively shaped, cylindrical or slightly depressed branches that vary in length from 5 to 20 cm and are white to white-greyish in colour, with infrequent soredia. The lichen has a cottony medulla, commonly white or sometimes pale yellowish-brown, and has frequent ascomata (fruiting bodies) with wavy margins.
| Roccella albida | |
|---|---|
| |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Arthoniomycetes |
| Order: | Arthoniales |
| Family: | Roccellaceae |
| Genus: | Roccella |
| Species: | R. albida |
| Binomial name | |
| Roccella albida Tehler (2009) | |
The lichen was formally described as a new species in 2009 by the mycologist Anders Tehler. The species epithet albida is derived from its whitish thallus, distinguishing it from the more brownish-grey thalli of its closely related species such as Roccella galapagoensis, R. margaritifera, and R. nigerrima.[2]
Roccella albida has a distinctively shaped thallus, which forms branches that are terete (cylindrical and smooth) or slightly foveate (marked with small depressions). These branches generally range in length from 5 to 20 cm and have a colouration that varies from white to white-greyish. Soredia, which are reproductive structures for asexual reproduction, are infrequently found in this species and show a negative reaction to the C spot test.[2]
The medulla, the inner tissue of the thallus, is byssoid or nearly byssoid, meaning it has a fibrous or cottony texture. Its colouration is predominantly white, though it can sometimes appear pale yellowish-brown, especially in the lower parts of the lichen. Ascomata, the spore-producing structures, are a common feature in Roccella albida. They often appear sessile (directly attached without a stalk) and have strongly undulating margins, which give them a knotty appearance. The ascospores of Roccella albida measure between 22 and 26 μm in length and 5 to 6 μm in width, with an average size of approximately 23.8 by 5.5 μm.[2]
Chemical spot tests yield negative results for the medulla with both potassium hydroxide (K) and calcium hypochlorite (C), indicated as K− and C−, respectively. However, the cortex is C+ (red), and K−. The disc of the ascomata is C−. In terms of its chemical makeup, Roccella albida contains secondary metabolites (lichen products) such as erythrin, lecanoric acid, and protocetraric acid, as identified by high-performance thin-layer chromatography.[2]
Roccella albida is native exclusively to the Galápagos Islands, with its presence confirmed on the islands Santa Fe, Floreana, Pinzón, Rábida, San Cristóbal, Santa Cruz, and Española.[3] This species thrives in coastal areas, predominantly on vertical rocks and cliffs.[2]
Seamless Wikipedia browsing. On steroids.
Every time you click a link to Wikipedia, Wiktionary or Wikiquote in your browser's search results, it will show the modern Wikiwand interface.
Wikiwand extension is a five stars, simple, with minimum permission required to keep your browsing private, safe and transparent.
