Acarospora

Acarospora
Acarospora glaucocarpa
Scientific classification
Kingdom:	Fungi
Division:	Ascomycota
Class:	Lecanoromycetes
Order:	Acarosporales
Family:	Acarosporaceae
Genus:	Acarospora A.Massal. (1852)
Type species
Acarospora schleicheri (Ach.) A.Massal. (1852)
Synonyms[1]
Gussonea Tornab. (1848)[2] Myriospora Nägeli (1853) Myriospora Nägeli ex Uloth (1861) Acarosporomyces Cif. & Tomas. (1953)

Acarospora is a genus of lichens in the family Acarosporaceae. Most species in the genus are crustose lichens that grow on rocks in open and arid places all over the world.^[3] They may look like a cobblestone road or cracked up old paint, and are commonly called cobblestone lichens or cracked lichens,.^[4]:216[5] They usually grow on rock (are "saxicolous"), but some grow on soil (terricolous) or on other lichens.^[3][4]:216 Some species in the genus are fungi that live as parasites on other lichens (lichenicolous fungi).^[3] Acarospora is a widely distributed genus, with about 128 species according to a 2008 estimate.^[6]

Species in Acarospora may be shiny as if covered with a glossy varnish, or dull and powdery looking. They have a diverse range of colors, from the brilliant yellow bright cobblestone lichen, to the dark reddish-brown mountain cobblestone lichen, or they can appear tan, gray, or white, from a dusty-looking coating (pruina).^[4]:216 They may grow in crustose forms like a warty surface (verrucose), like cracking-up old crust of paint (rimose), like a bunch of "islands" in a dry lake bed (areolate), like the flakes of cracking up paint are peeling up at the edges (sub-squamulous), or like the flakes are growing over others like scales (squamulous).

Growth form and appearance

The may grow as a warty crust (verrucose, a cracked crust rimose, or with the cracks separating island-like sections like in a dried lake (areolate – with the “islands” being called “areoles”).^[3] The areolas may lift up at the edges (sub-squamulose), and these edges may overlap other areolas like scales (squamulose, with the areoles being called “squamules”).^[3] The areoles may grow in lobes radiating from a center (placodioid. They may grow in irregular or indeterminate forms, sometimes with the areoles disconnected from each other and dispersed among other lichens.^[3] Sometimes the squamules may be elevated with expansion of the mycelial base above the substrate ("gomphate"), or aside on “stems” called stipes, which are usually about usually half the diameter of areole.^[3] The outer rim of the areola is usually down-turned.^[3]

They may be shiny or dull, and in many shades from pale to blackish brown.^[3] They may be smooth or rough (rugulose).^[3] They may be different colors from brilliant yellow (from rhizocarpic acid) to brown to white.^[3] They may or may not be covered with a powdery-looking surface (pruinose), which when present, may make them appear lighter in color, to almost white.^[3]

Internal structure

Like other crustose lichens, their cross section is generally divided into three layers, the cortex, photobiont layer, and medulla, and generally without a lower cortex as in foliose lichens.^[3] The cortex itself is usually differentiated, with three layers including a syncortex (sometimes absent), epinecral layer (sometimes absent, and eucortex, which is where the pigment is located in the upper parts.^[3] The photobiont of Acarospora are algae in the genus Trebouxia.^[7]

Fruiting structures

Each wart, areola, or squamule may have 0 to many apothecia.^[3] The apothecia are usually immersed in the thallus.^[3] Sometimes the apothecia are raised on a wart and surrounded by a margin of thallus-like tissue, sometimes with the margin being a true exciple.^[3] The apothecia are usually immersed, and round to very irregular in shape.^[4]:216 The apothecal disc is round to squished and irregular, and ranges in colors: black, brown, red, or yellow, or in-between. The disc may be smooth or it may be rough. The asci range from being narrow to being club shaped (clavate). Spores are colorless, spherical to ellipsoid, and range from tens to hundreds per ascus.^[4]:216

Taxonomy

The genus was published by Italian lichenologist Abramo Bartolommeo Massalongo in 1852, with the type species Acarospora schleicheri (originally described as Urceolaria schleicheri by Erik Acharius in 1810). Other species included by Massalongo in his original conception of the genus were A. chlorophana (now Pleopsidium chlorophanum), A. oxytona, A. cervina, A. smeragdula, and A. veronensis.^[8]

Chemistry

Acarospora species often lack secondary metabolites. Each wart, areola, or squamule may each have 0 to many apothecia.^[3] Some have norstictic acid, gyrophoric acid, or fatty acids. Each wart, areola, or squamule, may each have 0 to many apothecia.^[3] Yellow species have rhizocarpic acid, a pigment that makes them yellow. Each wart, areola, or squamule, may each have 0 to many apothecia.^[3]

Range and habitat

They grow all over the world, but usually in open arid habitats.^[3] They can grow on acidic rock and basic rock, or on soil.^[3]

Species

Yellow members of the genus may resemble members of Pleopsidium.^[4]:216 Non-yellow members may resemble members of Aspicilia.^[4]:216

List of Acarospora species

Acarospora affinis Acarospora americana Acarospora badiofusca Acarospora brattiae Acarospora brouardii Acarospora bullata Acarospora bylii Acarospora calcarea Acarospora capensis Acarospora cervina Acarospora chrysops Acarospora contigua Acarospora contraria Acarospora deserticola Acarospora dispersa Acarospora elevata Acarospora epilutescens Acarospora erythrophora Acarospora finckei Acarospora flavisparsa Acarospora fuscata Acarospora gallica Acarospora glaucocarpa Acarospora gwynnii Acarospora heufleriana Acarospora hilaris Acarospora hospitans Acarospora impressula Acarospora insolata Acarospora interspersa Acarospora janae Acarospora macrospora Acarospora nevadensis Acarospora nitrophila Acarospora nodulosa Acarospora novomexicana Acarospora obnubila Acarospora obpallens Acarospora oligospora Acarospora oligyrophorica Acarospora oreophila Acarospora oxytona Acarospora paupera Acarospora peliscypha Acarospora pseudofuscata Acarospora pyrenopsoides Acarospora rhabarbarina Acarospora rhizobola Acarospora robiniae Acarospora rouxii Acarospora schleicheri Acarospora scotica Acarospora sinopica Acarospora socialis Acarospora stapfiana Acarospora stictica Acarospora strigata Acarospora subrufula Acarospora succedens Acarospora terricola Acarospora thamnina Acarospora thelococcoides Acarospora tongletii Acarospora tuckerae Acarospora umbilicata Acarospora veronensis Acarospora verruciformis Acarospora versicolor Acarospora wetmorei

References

1. "Acarospora A. Massal., Ricerche sull'autonomia dei licheni crostosi: 27, 1852". MycoBank. International Mycological Association. Retrieved 2013-08-19.
2. Tornabene F. (1849). "Lichenographia Sicula". Atti della Accademia Giornia di Scienze Naturali Catania 2: 22.
3. Acarospora, Lichen Flora of the Greater Sonoran Desert Region. Vol 3, Nash, T.H., Ryan, B.D., Gries, C., Bugartz, F., (eds.) 2001,
4. Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, ISBN 978-0-300-19500-2
5. Name Search Results for Scientific Name Acarospora, USDA
6. Kirk PM, Cannon PF, Minter DW, Stalpers JA. (2008). Dictionary of the Fungi (10th ed.). Wallingford, UK: CAB International. p. 3. ISBN 978-0-85199-826-8.
7. Thomson JW. (1984). American Arctic Lichens: The Microlichens. University of Wisconsin Press. p. 19. ISBN 978-0-299-13460-0.
8. Massalongo AB. (1852). Ricerche sull'autonomia dei licheni crostosi (in Italian). Verona: Frizerio. p. 27.

External links

• Acarospora in Index Fungorum