Endocarpon Petrolepideum

''Endocarpon'' is a genus of saxicolous (rock-dwelling), squamulose lichens in the family Verrucariaceae. It comprises 23 species.

Taxonomy

The genus was circumscribed by the German bryologist Johann Hedwig in 1789. '' Endocarpon pusillum'' was assigned as the type species.

Description

Lichens in the genus ''Endocarpon'' have a thallus, meaning their body is made up of small, scale-like lobes. These lobes typically lie flat against the surface they grow on but can sometimes be slightly raised. In rare cases, the thallus may take on a more leaf-like (subfoliose) form. The outer layer of the lichen, the , is composed of roughly spherical cells. Beneath this, the inner tissue ( medulla) may contain similar cells or more elongated ones. Unlike some lichens, ''Endocarpon'' species often lack a distinct lower cortex, though they may have a loosely arranged layer of rounded or angular cells. Many species produce rhizines—small, root-like structures that help anchor the lichen to its .

The lichen's photosynthetic partner is '' Diplosphaera'', a type of green alga in the Trebouxiophyceae. This alga is found not only within the thallus but also within the reproductive structures, often forming column-like arrangements inside the lichen's body.

''Endocarpon'' lichens reproduce through small, rounded fruiting bodies called perithecia, which are embedded within the thallus. These structures have a tiny pore (ostiole) at the top, which allows spores to be released. The outer layer of the perithecia () is dark in colour throughout, and unlike some related lichens, ''Endocarpon'' lacks an outer protective layer called an . Inside, the spore-producing tissue (hymenium) reacts with iodine-based stains, turning reddish or bluish with iodine (I+) and blue with potassium iodide (K/I+). Unlike many lichens, the reproductive structures do not contain paraphyses (sterile filaments), but they do have numerous —small hair-like structures lining the opening of the perithecia.

The spores of ''Endocarpon'' are typically produced in groups of one or two per ascus (though occasionally up to four). They are enclosed in a thick-walled, sac-like structure (ascus) that splits open to release them. The spores themselves are , meaning they are divided into multiple compartments by internal walls (septa), and they can be colourless, yellowish-brown, or dark brown. In addition to sexual reproduction, ''Endocarpon'' can also produce asexual spores (conidia) within specialised structures called pycnidia, which are also embedded in the thallus. These conidia are tiny, rod-shaped, colourless, and lack internal divisions. Chemically, ''Endocarpon'' does not produce any secondary metabolites detectable through thin-layer chromatography.

Species

, Species Fungorum (in the Catalogue of Life) accept 23 species of ''Endocarpon''.

* '' Endocarpon adscendens''
* '' Endocarpon aridum'' – Australia
* '' Endocarpon baicalense''
* '' Endocarpon crassisporum'' – Australia
* '' Endocarpon crystallinum'' – China
* '' Endocarpon deserticola'' – China
* '' Endocarpon helmsianum''
* '' Endocarpon macrosporum'' – Australia
* '' Endocarpon maritimum'' – South Korea
* '' Endocarpon muelleri''
* '' Endocarpon myeloxanthum'' – Mexico
* '' Endocarpon pallidulum''
* '' Endocarpon pallidum''
* '' Endocarpon pseudosubnitescens'' – Mexico
* '' Endocarpon pusillum''
* '' Endocarpon riparium'' – Brazil
* '' Endocarpon robustum'' – Australia
* '' Endocarpon rogersii'' – Australia
* '' Endocarpon simplicatum''
* '' Endocarpon subramulosum'' – South Korea
* ''Endocarpon tenuissimum''
* '' Endocarpon unifoliatum'' – China
* '' Endocarpon zschackei''

References

Gallery

Image:Endocarpon_petrolepideum-4.jpg, Two muriform spores in an ascus from ''E. petrolepideum''; photographed through a compound microscope, x1000

{{Taxonbar , from1=Q5376227 , from2=Q76436688

Verrucariales
Eurotiomycetes genera
Lichen genera
Taxa named by Johann Hedwig
Taxa described in 1789