''Xanthoparmelia conspersa'', commonly known as the peppered rock-shield, is a
foliose lichen
A foliose lichen is a lichen with flat, leaf-like , which are generally not firmly bonded to the substrate on which it grows. It is one of the three most common growth forms of lichens. It typically has distinct upper and lower surfaces, each o ...
and the
type species
In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...
of genus ''
Xanthoparmelia
''Xanthoparmelia'' (commonly known as green rock shields or rock-shield lichens) is a genus of foliose lichens in the family Parmeliaceae.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, This genus of lichen i ...
''. It is widely distributed in
temperate
In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...
zones, and has been recorded from Japan, Europe, Africa, North America, and South America.
Taxonomy
The lichen was first
described with the name ''Lichen conspersus'' in 1799 by lichenologist
Erik Acharius
Erik Acharius (10 October 1757 – 14 August 1819) was a Swedish botanist who pioneered the Taxonomy (biology), taxonomy of lichens and is known as the "father of lichenology". Acharius was famously the last pupil of Carl Linnaeus.
Life
Ac ...
.
In its taxonomic history, it has been transferred to the genera ''Imbricaria'', ''
Lobaria'', and ''
Parmelia''.
It became known as a species of ''Xanthoparmelia'' when
Mason Hale promoted that subgenus of ''Parmelia'' to generic status in 1974.
It is
commonly known as the "peppered rock-shield".
Description
''Xanthoparmelia conspersa'' has a
thallus
Thallus (: 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. A thallus usually names the entir ...
that is either tightly or loosely attached to its substrate. The thallus, which measures , is made of narrow lobes that are 1–3 mm wide, which are crowded and usually overlapping. The thallus upper surface often features
isidia
An isidium (plural: isidia) is a tiny, wart- or finger-like outgrowth on the thallus surface of certain lichen species. It is one of two principal types of vegetative reproduction, vegetative reproductive structures in lichens, the other being ...
that range in shape from spherical to branched cylinders. The lower surface of the thallus is black, except for near the lobe tips, where it may be pale to dark brown.
Rhizine
In lichens, rhizines are multicellular root-like structures arising mainly from the lower surface. A lichen with rhizines is termed rhizinate, while a lichen lacking rhizines is termed erhizinate. Rhizines serve only to anchor the lichen to their s ...
s are coarse, black, and simple (i.e., unbranched), with a length of 0.5–1 mm.
Ascospore
In fungi, an ascospore is the sexual spore formed inside an ascus—the sac-like cell that defines the division Ascomycota, the largest and most diverse Division (botany), division of fungi. After two parental cell nucleus, nuclei fuse, the ascu ...
s are 5–6 by 9–10
μm.
Some
secondary metabolites
Secondary metabolites, also called ''specialised metabolites'', ''secondary products'', or ''natural products'', are organic compounds produced by any lifeform, e.g. bacteria, archaea, fungi, animals, or plants, which are not directly involved ...
found in ''Xanthoparmelia conspersa'' include
usnic acid
Usnic acid is a naturally occurring dibenzofuran derivative found in several lichen species with the formula C18H16O7. It was first isolated by German scientist W. Knop in 1844 and first synthesized between 1933 and 1937 by Frank H. Curd and Al ...
,
hyposalazinic acid,
stictic and
norstictic acid
Norstictic acid is a depsidone produced as a secondary metabolites in lichens. The compound contains both an aldehyde carbonyl group and an adjacent hydroxyl
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical fo ...
.
Habitat and distribution
''Xanthoparmelia conspersa'' grows on rocks (on
siliceous rock
Siliceous rocks are sedimentary rocks that have silica (SiO2) as the principal constituent. The most common siliceous rock is chert; other types include diatomite. They commonly form from silica-secreting organisms such as radiolarians, diatoms, o ...
s, particularly
granite
Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...
), and is typically found in sunny habitats.
It has been recorded from Asia (Japan), Europe, Africa, North America, and South America.
See also
*
List of ''Xanthoparmelia'' species
References
{{Taxonbar, from=Q10542533
conspersa
Lichen species
Lichens described in 1799
Lichens of Africa
Lichens of Europe
Lichens of Japan
Lichens of North America
Lichens of South America
Taxa named by Erik Acharius