''Verrucula arnoldaria'' is a rare species of lichenicolous (lichen-dwelling)
lichen
A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.Verrucariaceae
The Verrucariaceae are a family of mostly lichenised fungi in the order Verrucariales. The lichen-forming species, which comprise the vast majority of the family, have a wide variety of thallus forms, and include crustose (crust-like), foliose ( ...
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 ...
crustose lichen
Crustose lichens are lichens that form a crust which strongly adheres to the Substrate (biology), substrate (soil, rock, tree bark, etc.), making separation from the substrate impossible without destruction. The basic structure of crustose lichen ...
Claude Roux
Claude Roux is a French lichenologist, mycologist and Esperantist. He has co-authored books about the identification of lichens written in Esperanto.
Career
Between 1969 and 1975 Roux was employed as a biology and geology teacher in a secondary ...
, from specimens collected in
Vaucluse
Vaucluse (; oc, Vauclusa, label= Provençal or ) is a department in the southeastern French region of Provence-Alpes-Côte d'Azur. It had a population of 561,469 as of 2019. It has also been recorded from Italy. The lichen has a thick brownish-grey,
areolate
Lichens are composite organisms made up of multiple species: a fungal partner, one or more photosynthetic partners, and sometimes a basidiomycete yeast. They are regularly grouped by their external appearance – a characteristic known as their ...
thallus that roughly maintains the shape of its underlying
host
A host is a person responsible for guests at an event or for providing hospitality during it.
Host may also refer to:
Places
* Host, Pennsylvania, a village in Berks County
People
*Jim Host (born 1937), American businessman
* Michel Host ...
. The thallus is covered with a crystalline pruina. It makes
ellipsoid
An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation.
An ellipsoid is a quadric surface; that is, a surface that may be defined as the ...
spores that measure up to about 15
μm
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...
long. Its host grows on
calciferous
Calciferous sandstone is a geological term relating to strata at the base of the Carboniferous formation, below the entire sequence of coal measures. This term may be unique to the UK.
Typically this part of the geological sequence, as in the Tou ...
rocks and calciferous
schist
Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes o ...