''Chaenotheca furfuracea'' is a mealy (

farinaceous Flour is a powder made by grinding raw grains, roots, beans, nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredient of bread, which is a staple food for many cultures. ...

), bright yellow-green leprose

pin lichen Lichens are symbiotic organisms made up of multiple species: a fungus, one or more photobionts (an alga and/or a cyanobacteria) and sometimes a yeast. They are regularly grouped by their external appearance – a characteristic known as their gro ...

.Lichen Flora of the Greater Sonoran Desert Region. Vol 2, Nash, T.H., Ryan, B.D., Gries, C., Bugartz, F., (eds.) 2001

/ref> It is in the family Coniocybaceae. This distinctive lichen forms vivid yellow-green powdery crusts on tree bark and produces tiny pin-like fruiting bodies up to 2 mm tall, each with a hair-thin stalk topped by a spherical head. It grows in damp, deeply shaded locations such as tree root crevices and rocky overhangs, particularly in upland areas of Europe where it grows mainly on

beech Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...

es,

oak An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...

s, and

spruce A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal ecosystem, boreal (taiga) regions of the Northern hemisphere. ''Picea'' ...

roots.

Description

''Chaenotheca furfuracea'' forms a loose, powdery ( leprose) crust that spreads across bark as a vivid yellow-green stain. The photobiont—the lichen's algal partner—is a species of ''

Stichococcus ''Stichococcus'' is a genus of green algae in the family Stichococcaceae. It is a very common algal genus found in a variety of habitats, such as tree trunks, soil, snow, freshwater and marine habitats. One species, '' Stichococcus bacillaris'' ...

'', whose tiny green cells sit just below the surface and provide photosynthate. Rising from the crust are pin-like fruiting bodies up to about 2 mm tall. Each comprises a hair-fine stalk (roughly one-tenth of a millimetre thick) that is sheathed in a yellow-green, frost-like coating of crystalline pigment called ; the stalk appears black where this coating wears away. At the tip sits a near-spherical head only 0.1–0.2 mm across. Its outer rim () is so poorly developed that it is scarcely visible, and the interior spore mass () begins life dusted with the same yellow-green pruina before ageing to a pale brown. Under the microscope the spore-producing sacs ( asci) are irregular in outline and develop in chains rather than singly. Each ascus releases numerous microscopic

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 that are spherical, only 2.3–3

μm The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...

in diameter, and ornamented with a maze of fine ridges () that may look like tiny warts under a light microscope. The lichen lacks specialised

conidiomata Conidiomata (singular: Conidioma) are blister-like fruiting structures produced by a specific type of fungus called a coelomycete. They are formed as a means of dispersing asexual spores call conidia, which they accomplish by creating the blister- ...

—structures that many fungi use for

asexual Asexual or Asexuals may refer to: *Asexual reproduction **Asexual reproduction in starfish *Asexuality, the lack of sexual attraction to anyone or lack of interest in or desire for sexual activity. **Gray asexuality, the spectrum between asexualit ...

propagation—but does form simple, upright threads (

conidiophore A conidium ( ; : conidia), sometimes termed an asexual chlamydospore or chlamydoconidium (: chlamydoconidia), is an Asexual reproduction, asexual, non-motility, motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word f ...

s) that bud off colourless, ellipsoidal

conidia A conidium ( ; : conidia), sometimes termed an asexual chlamydospore or chlamydoconidium (: chlamydoconidia), is an asexual, non- motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also ...

in loose chains. Chemical spot tests reveal the presence of

vulpinic acid Vulpinic acid is a natural product first found in and important in the symbiosis underlying the biology of lichens. It is a simple methyl ester derivative of its parent compound, pulvinic acid, and a close relative of pulvinone, both of which de ...

pulvinic acid Pulvinic acids are natural chemical pigments found in some lichens, derived biosynthetically from the aromatic amino acids phenylalanine and tyrosine, via dimerization and oxidative ring-cleavage of arylpyruvic acids, a process that also produces ...

, and pulvinic dilactone in both the crust and the pruina, compounds that lend the species its characteristic yellow-green hue.

Ecology

The species can be found in European countries like

Belgium Belgium, officially the Kingdom of Belgium, is a country in Northwestern Europe. Situated in a coastal lowland region known as the Low Countries, it is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeas ...

Luxembourg Luxembourg, officially the Grand Duchy of Luxembourg, is a landlocked country in Western Europe. It is bordered by Belgium to the west and north, Germany to the east, and France on the south. Its capital and most populous city, Luxembour ...

, and

Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...

. The species are growing mostly on

es and

s, and on tree roots of

s. They also grow on

detritus In biology, detritus ( or ) is organic matter made up of the decomposition, decomposing remains of organisms and plants, and also of feces. Detritus usually hosts communities of microorganisms that colonize and decomposition, decompose (Reminera ...

or sand, and in rare cases on fissures of

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. It does better in climates with high humidity and low

luminosity Luminosity is an absolute measure of radiated electromagnetic radiation, electromagnetic energy per unit time, and is synonymous with the radiant power emitted by a light-emitting object. In astronomy, luminosity is the total amount of electroma ...

. ''Chaenotheca furfuracea'' usually occupies damp, deeply shaded nooks—tucked into crevices between tree roots or on rocky faces beneath overhangs—and is encountered most often in upland areas.

References

{{Taxonbar, from=Q5066575 Coniocybaceae Lichen species Lichens described in 1753 Lichens of Europe Taxa named by Carl Linnaeus