''Wahlenbergiella tavaresiae'' is a species of

saxicolous A saxicolous lichen is a lichen that grows on rock. The prefix "sax" from the Latin means "rock" or "stone". Characteristics Saxicolous lichens exhibit very slow growth rates. They may develop on rock substrates for long periods of time, give ...

(rock-dwelling),

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 ...

in the family

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 ( ...

. Known from several locations in the

San Francisco Bay San Francisco Bay is a large tidal estuary in the U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, and Oakland. San Francisco Bay drains water from a ...

area of the United States, it is a marine lichen that inhabits

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species o ...

s, and as such is immersed in seawater on a regular basis. Associated algal species include the

red algae Red algae, or Rhodophyta (, ; ), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority ...

Hildenbrandia ''Hildenbrandia'' is a genus of thalloid red alga comprising about 26 species. The slow-growing, non-mineralized thalli take a crustose form. ''Hildenbrandia'' reproduces by means of conceptacles and produces tetraspores. Morphology ''Hildenb ...

'' and ''

Mastocarpus papillatus ''Mastocarpus papillatus'', sometimes called Turkish washcloth, black tar spot, or grapestone is a species of red algae in the family Phyllophoraceae. It is sometimes confused with the distantly related ''Turkish towel'' ('' Chondracanthus ex ...

'', and the

brown algae Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and po ...

'' Pelvetiopsis'' and ''

Fucus ''Fucus'' is a genus of brown algae found in the intertidal zones of rocky seashores almost throughout the world. Description and life cycle The thallus is perennial with an irregular or disc-shaped holdfast or with haptera. The erect portion o ...

''. '' Petroderma maculiforme'', a brown alga, is the

photobiont A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.

Taxonomy

The lichen was first formally described as a new species in 1997 by Richard Moe from specimens collected from Franciscan sandstone at the upper intertidal zone of

Fort Mason Fort Mason, in San Francisco, California originated as a coastal defense site during the American Civil War. The nucleus of the property was owned by John C. Frémont and disputes over compensation by the United States continued into 1968. In 188 ...

San Francisco San Francisco (; Spanish language, Spanish for "Francis of Assisi, Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the List of Ca ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, in 1975. The species epithet honors mycologist and lichenologist Isabelle Tavares of the Herbarium of the University of California at Berkeley, who introduced the author to the study of lichens. In 2011,

Cécile Gueidan Cécile Gueidan is a mycologist and lichenologist who applies morphological and molecular biological methods to the origin and taxonomy of fungi that live in lichen symbioses and within rocks. Early life and education Gueidan began working on ...

, Holger Thüs, and Sergio Pérez-Ortega transferred the

taxon In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

to the genus ''

Wahlenbergiella ''Wahlenbergiella'' is a genus of saxicolous (rock-dwelling), crustose lichens in the family Verrucariaceae. It has three species, all of which live in marine intertidal zones where they get periodically immersed in seawater. ''Wahlenbergiella'' ...

'', following a

molecular phylogenetics Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

-led revision of several genera of the family Verricariaceae.

Description

The lichen, when wet, is dark brownish to greenish black; after exposure to dry air, it becomes initially matte black before lightening. The crust-like

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 ...

measures 0.25–1 mm thick, and adheres tightly to the rock substrate. The photobiont cells are more or less restricted to a distinct layer in the

medulla Medulla or Medullary may refer to: Science * Medulla oblongata, a part of the brain stem * Renal medulla, a part of the kidney * Adrenal medulla, a part of the adrenal gland * Medulla of ovary, a stroma in the center of the ovary * Medulla of th ...

. The frequency of

perithecia An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mo ...

ranges from sparse to crowded; they are flask-shaped and completely immersed in the thallus, measuring 300–500

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 ...

in diameter. The

asci ASCI or Asci may refer to: * Advertising Standards Council of India * Asci, the plural of ascus, in fungal anatomy * Accelerated Strategic Computing Initiative * American Society for Clinical Investigation * Argus Sour Crude Index * Association of ...

are club-shaped (''clavate'') and 40 µm long, containing eight spores. Initially spherical, the

ascospore An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or s ...

s become

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 ...

, with dimensions of 12–15 µm by 5–7 µm.

References

{{Taxonbar, from=Q21301265 Verrucariales Lichen species Lichens described in 1997 Lichens of the Southwestern United States