''Rusavskia sorediata'' is a species of saxicolous (rock-dwelling), crustose lichen in the family

Teloschistaceae The Teloschistaceae are a large family of mostly lichen-forming fungi belonging to the class Lecanoromycetes in the division Ascomycota. The family, estimated to contain over 1800 species, was extensively revised in 2013, including the creation o ...

. It is widely distributed in the Northern Hemisphere. The lichen was first formally described by the Finnish lichenologist

Edvard August Vainio Edvard August Vainio (born Edvard Lang; 5 August 185314 May 1929) was a Finnish lichenology, lichenologist. His early works on the lichens of Lapland (Finland), Lapland, his three-volume monograph on the lichen genus ''Cladonia'', and, in parti ...

in 1881, as ''Lecanora elegans'' var. ''sorediata''. Gustaf Einar Du Rietz transferred it to ''

Caloplaca ''Caloplaca'' is a lichen genus comprising a number of distinct species. Members of the genus are commonly called firedot lichen, jewel lichen.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, gold lichens, "ora ...

'' in 1916. Josef Poelt considered it better in genus '' Xanthoria'', and it was known by that binomial for several decades. In 2003,

Sergey Kondratyuk Sergey Yakovlevich Kondratyuk ( uk, Сергій Якович Кондратюк) (born 17 May 1959) is a Ukrainian botanist specialising in lichenology. His research deals with the taxonomy, floristics, ecology and geography of lichens and lic ...

and

Ingvar Kärnefelt Jan Eric Ingvar Kärnefelt (born 1944) is a Swedish lichenologist. Early life and education Kärnefelt was born in Gothenburg, Sweden in 1944. His initial goal in his higher-level studies at University of Cologne in 1966–1967 was to become ...

transferred it to their newly

circumscribed In geometry, the circumscribed circle or circumcircle of a polygon is a circle that passes through all the vertices of the polygon. The center of this circle is called the circumcenter and its radius is called the circumradius. Not every polyg ...

genus ''

Rusavskia ''Rusavskia'' is a genus of lichen-forming fungi in the family Teloschistaceae. It has 12 species. It is a member of the subfamily Xanthorioideae. The thallus of ''Rusavskia'' is characterized by its foliose lichen, foliose (leaf-like) structu ...

''. The lichen develops small, spherical pustules on its surface, which eventually become soredia. These soredia can range in abundance from hardly there to covering nearly the entire thallus surface. Because of the characteristic appearance imparted by these granular

propagule In biology, a propagule is any material that functions in propagating an organism to the next stage in its life cycle, such as by dispersal. The propagule is usually distinct in form from the parent organism. Propagules are produced by organisms ...

s, in North America, a

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

used for this species is sugared sunburst lichen. ''Rusavskia sorediata'' has a Arctic-oreophytic distribution; "oreophytic" refers to plants (and by extension, lichens or other organisms) that are adapted to live in mountainous regions, especially those growing above the

forest line The tree line is the edge of the habitat at which trees are capable of growing. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually cold temperatures, extreme snowp ...

but below the permanent

snow line The climatic snow line is the boundary between a snow-covered and snow-free surface. The actual snow line may adjust seasonally, and be either significantly higher in elevation, or lower. The permanent snow line is the level above which snow wil ...

. It has been recorded in Asia, Europe, North America, and Greenland.

References

{{Taxonbar , from=Q21304636 , from2=Q108619218 , from3=Q107539692 , from4=Q10509597 Teloschistales Lichen species Lichens described in 1881 Lichens of Asia Lichens of Europe Lichens of North America Lichens of Subarctic America Taxa named by Edvard August Vainio