Pseudocyphellaria and Reactive devaluation

Pseudocyphellaria is a genus of large, leafy lichens that are sometimes referred to as "specklebelly" lichens. The genus has a widespread distribution, especially in south temperate regions, and contains about 170 species. They resemble Lobaria, except that all species of Pseudocyphellaria have conspicuous pseudocyphellae on their lower surface, a characteristic that is unique to this genus. Some species contain pulvinic acid-related pigments; in these species the soredia and pseudocyphellae can be bright yellow.

Contents 1 The Pseudocyphellaria symbiosis 2 Ecological significance 3 Traditional use by humans 4 Gallery 5 References 6 External links

The Pseudocyphellaria symbiosis

Many species of Pseudocyphellaria are cyanolichens and contain the cyanobacterium Nostoc as a photobiont, which allows nitrogen fixation. In some species of Pseudocyphellaria the cyanobacterium is the sole photobiont, while other species also contain the green alga Dictyochloropsis and restrict the cyanobacterium to warty cephalodia on the lower surface of the lichen.

Some species of Pseudocyphellaria appear to be able to use either a cyanobacterium or a green algae as their photobiont. DNA tests have shown that the fungal symbionts in P. murrayi (which is in a symbiosis with a cyanobacterium) and P. rufovirescens (which is in a symbiosis with a green alga) are actually the same species. This means that P. murrayi-P. rufovirescens is actually one species of fungus that is capable of forming two very different lichens, one with a cyanobacterium and one with a green alga. Two other possible pairs of Pseudocellaria species that may be capable of choosing their photobiont are P. knightii-P. lividofusca, and P. kookeri-P. durietzii. Ecological significance

Most Pseudocyphellaria grow on trees in coastal areas, from the subtropics to the boreal zones, although some species can occasionally be found growing on mossy rocks or growing inland. Many species of Pseudocyphellaria are restricted to old-growth forests in humid areas, and are therefore threatened by logging. The limited light conditions of dense young forests can severely decrease the growth of Pseudocyphellaria crocata compared to more open, old-growth forests, and the excess of light from clearcuts can also cause damage to the lichen. Because they are often restricted to humid forests in undisturbed areas, species of Pseudocyphellaria are often used as indicators of valuable old growth forests.

Pseudocyphellaria rainierensis is listed as vulnerable in Canada by COSEWIC. Pseudocyphellaria crocata has disappeared from much of Scandinavia, a development that has been partly attributed to an increase in grazing from snails, presumably as a result of global warming. In the areas of Scandinavia where P. crocata is still found, it seems restricted to growing on smaller twigs that are harder for the snails to reach. Traditional use by humans

Several species of Pseudocyphellaria can be utilized to produce a brown to orange-brown dye, and some of them have been used to dye wool in Britain and Scandinavia. One species of Pseudocyphellaria is used in Madagascar to make a tea used to treat indigestion.

Warning: Besides being yellow, pulvinic acid derivatives are highly toxic. Any species of Pseudocyphellaria that has yellow structures probably contains one of these compounds, and may be toxic if ingested. Gallery

Pseudocyphellaria corifolia growing in Parque Etnobotanico Omora on Isla Navarino, Chile. This species has brown soralia and black apothecia.

Pseudocyphellaria granulata growing in Parque Etnobotanico Omora on Isla Navarino, Chile. This species has brilliant yellow soralia.

A species of Pseudocyphellaria growing in the Patagonian Andes near Bariloche, Argentina. This species has brilliant yellow soralia.

Yellow pseudocyphellea on the underside of a species of Pseudocyphellaria growing near Bariloche, Argentina.

Reactive devaluation and Pseudocyphellaria

Reactive devaluation is a cognitive bias that occurs when a proposal is devalued if it appears to originate from an antagonist. The bias was proposed by Lee Ross and Constance Stillinger.

In an initial experiment conducted in 1991, Stillinger and co-authors asked pedestrians whether they would support a drastic bilateral nuclear arms reduction program. If they were told the proposal came from President Ronald Reagan, 90 percent said it would be favorable or even-handed to the United States; if they were told the proposal came from a group of unspecified policy analysts, 80 percent thought it was favorable or even; but, if respondents were told it came from Mikhail Gorbachev only 44 percent thought it was favorable or neutral to the United States.

In another experiment, a contemporaneous controversy at Stanford University led to the university divesting of South African assets because of the apartheid regime. Students at Stanford were asked to evaluate the university's divestment plan before it was announced publicly and after such. Proposals including the actual eventual proposal were valued more highly when they were hypothetical.

In another study, experimenters showed Israeli participants a peace proposal which had been actually proposed by Israel. If participants were told the proposal came from a Palestinian source they rated it lower than if they were told (correctly) the identical proposal came from the Israeli government. If participants identified as "hawkish" were told it came from "dovish" Israeli government they believed it was relatively bad for their people and good for the other side, but not if participants identified as "doves".

Reactive devaluation could be caused by loss aversion or attitude polarization, or naïve realism.
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