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The lichenometrist Tom Bradwell has listed the following five method families as the principal ones into which most other methods can be classified: Largest lichen (LL): When the single largest lichen of a species is used it means that the lichen that is oldest or grows in most favorable conditions is used to date the minimum age of the exposed ...
Lichens are a common source of natural dyes.The lichen dye is usually extracted by either boiling water or ammonia fermentation.Although usually called ammonia fermentation, this method is not actually a fermentation and involves letting the lichen steep in ammonia (traditionally urine) for at least two to three weeks.
Examples of lichen substances that give a bright fluorescence in UV are alectoronic, lobaric, and divaricatic acids, and lichexanthone. In some cases, the UV light test can be used to help distinguish between closely related species, such as Cladonia deformis (UV−) and Cladonia sulphurina (UV+, due to presence of squamatic acid). [19]
One reason the greenshield lichen can be more commonly found than other lichen species is because it is relatively tolerant of pollution. Lichens are often used to monitor air quality. Since ...
Methods for species identification include reference to single-access keys on lichens. An example reference work is Lichens of North America (2001) by Irwin M. Brodo, Sylvia Sharnoff and Stephen Sharnoff and that book's 2016 expansion, Keys to Lichens of North America: Revised and Expanded by the same three authors joined by Susan Laurie ...
Many lichens are very sensitive to environmental disturbances and can be used to cheaply [16] assess air pollution, [56] [57] [58] ozone depletion, and metal contamination. Lichens have been used in making dyes, perfumes , [59] and in traditional medicines. A few lichen species are eaten by insects [16] or larger animals, such as reindeer. [60]
Lichenometry is based on the assumption that the largest lichen growing on a rock is the oldest individual. Generally, the five largest lichen thalli diameters are taken, although several statistical methods have been used. If the growth rate is known, the maximum lichen size will give a minimum age for when this rock was deposited.
A small gall-like structure that contains cyanobacteria, found in some lichens. These structures can be located on the lichen's upper or lower surface, or within the thallus itself. [68] These structures are found in most lichens that contain both algal and cyanobacterial photobionts. [91] The term was first used by Erik Acharius in 1803. [3 ...