lichen
A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.fungi in the family
Pilocarpaceae
The Pilocarpaceae are a family of crustose lichens in the order Lecanorales. The species of this family have a cosmopolitan distribution and have been found in a variety of climatic regions. Pilocarpaceae was circumscribed by Alexander Zahlbruck ...
. It has three species, which occur in Europe and North America. The genus was
circumscribed
In geometry, the circumscribed circle or circumcircle of a polygon is a circle that passes through all the vertices of the polygon. The center of this circle is called the circumcenter and its radius is called the circumradius.
Not every polyg ...
in 2018 by
André Aptroot
André Aptroot (Heemskerk, 1961) is a Dutch mycologist and lichenologist.
In 1993 he did his PhD at the University of Utrecht under the supervision of Robbert Gradstein (nl). His dissertation was titled "Systematic studies on pyrenocarpous li ...
to contain a small group of ''
Bacidia
''Bacidia'' is a genus of lichen-forming fungi in the family Ramalinaceae. The genus was circumscribed by Giuseppe De Notaris in 1846. Species in the genus are crust-like lichens with stemless apothecia; they have green algae (chloroccoid) as p ...
'' species that formed a distinct
lineage
Lineage may refer to:
Science
* Lineage (anthropology), a group that can demonstrate its common descent from an apical ancestor or a direct line of descent from an ancestor
* Lineage (evolution), a temporal sequence of individuals, populati ...
in the Pilocarpaceae. The type species is '' Aquacidia trachona'', a lichen that was originally described in 1803 by Erik Acharius as ''Verrucaria trachona''. The genus name ''Aquacidia'' refers to the habitat of the species, which is typically on rocks near water. Lichens in this genus can form thalli that cover vast areas of
substrate
Substrate may refer to:
Physical layers
*Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached
** Substrate (locomotion), the surface over which an organism lo ...
. For example, in Holland, the lichens can form large colonies in sheltered rock crevices between boulders in
dikes
Dyke (UK) or dike (US) may refer to:
General uses
* Dyke (slang), a slang word meaning "lesbian"
* Dike (geology), a subvertical sheet-like intrusion of magma or sediment
* Dike (mythology), ''Dikē'', the Greek goddess of moral justice
* Dikes, ...
.
Species
*''
Aquacidia antricola
''Aquacidia'' is a genus of lichen-forming fungi in the family Pilocarpaceae. It has three species, which occur in Europe and North America. The genus was circumscribed in 2018 by André Aptroot to contain a small group of ''Bacidia'' species t ...