The Biogeography of the Lace Lichen (R. menziesii).
by Stefanie Egan, student in
Geography 316 Fall 2003
Thank you for visiting our site. This web page was written by a student in Geography 316: Biogeography and edited by the instructor, Barbara Holzman, PhD. All photos and maps are posted with specific copyright permission for the express use of education on these web pages. The students have tried to be as accurate as possible with the information provided and sources and references are cited at the end of each page.
Species Name: Ramalina menziesii
Species: Ramalina menziesii
Description of Species:
Although it is a true lichen, Ramalina menziesii. is commonly known as both Lace Lichen and Spanish Moss, perhaps for its rather soft appearance and greenish color. Although its morphology is quite variable, generally speaking this lichen hangs from its host in long, branching strands that can reach up to 2 meters in length. If examined very closely, R. menziesii resembles an elongated, greenish-yellow piece of material with many holes in it.
Ramalina menziesii is a fruticose, epiphytic lichen commonly found on oaks, shrubs, conifers and broadleaf trees of the foothill and valley woodlands as well as the North Coast forests of California (Hale & Cole 1988). R. menziesii is most prevalent on damp, coastal facing slopes of the aforementioned habitats, and will often be absent in the driest of these areas (Hale & Cole 1988). It can be found in these habitats from sea level to about 3500 feet.
Lichens by their nature are rather anomalous organisms. Not just one organism, lichens are actually a combination of a fungus, or mycobiont, and a photosynthetic organism, or photobiont (De Santis 1999). A lichen is formed when a mycobiont envelops either green algae or cyanobacteria. This combination allows for the new organism (the lichen) to provide its own food source through photosynthesis. Although lichens have historically been viewed as partnerships of a sort, it is now believed they are an example of a “controlled parasitic” situation (De Santis 1999).
Its morphology provides R. menziesii. with a large surface area from which it can retrieve nutrients carried by airborne elements, such as precipitation and dust (Boucher and Nash 1990). When parts of the lichen drop to the ground around the base of the host, its decomposition provides essential nutrients to the host, thereby creating a mutually beneficial relationship (Boucher and Nash 1990). I would hazard to say that R. menziesiienziesii’s morphology is a particular adaptation to the West coast of North America, as it is restricted in its distribution to this area (Larson 1983). Given the often moist and strong westerly winds that blow throughout this region, its pendulous and porous nature has allowed it to capitalize on this phenomenon by enabling capture of nutrients borne by particles carried by the winds.
Reproduction by this species can be accomplished both sexually and asexually. When done asexually, parts of the thallus (the main plant body) that have broken free of the organism recombine to form a new organism (De Santis 1999). Sexual reproduction occurs when fungal spores are released and find a new photobiont with which to combine (De Santis 1999).
Human use of lichen dates back to the earliest of civilizations. Early Egyptians used lichen for food when other sources were scarce (Seaward 1977). They have been used for dyes, as perfume sources, for medicinal purposes as well as for alcohol production (Seaward 1977). Specifically, Ramalina menziesii was used by various Native American tribes of California: the Kawaiisu, for example used this species for what they believed to be its magical properties. They would place the lichen in water in order to bring the rains, or throw it into fire to prevent thunder and lightening (Sharnoff 2003). Another Indian tribe from California, the Kashaya Pomo, was known to use R. menziesii. to produce fiber, specifically for baby diapers and other sanitary uses of that nature (Sharnoff 2003).
Lichens belong to the Class Ascomycetes, fungi that can form lichen, of which there are many (13 orders, to be exact) indicating to scientists that lichens have not evolved from a common ancestor (Brodo et al. 2001). As a result, lichens are not considered a taxonomic unit, as their unifying factor stems from the manner in which they derive food, and not a common ancestry (Brodo et al. 2001).
Lichens are essentially the result of a process; the union of two organisms, a fungus and an algae. To trace the evolution of lichens, then, it is necessary to establish when Ascomycota, the primary type of fungi that form lichens, began to engage in this symbiotic relationship. It appears that the evolution of both Ascomycota and lichens is a complex and as yet little understood process that is currently being pieced together. Current research indicates that lichens appeared a number of different times, which researchers believe accounts for why there are such a broad array of Ascomycota that form lichens and those that do not (Lutzoni et al. 2001). In fact, while the Ascomycota fungi were evolving there was not much lichen formation.
In terms of Ascomycota evolution, lichenization impacted the development of these fungi, as those that do not form lichens appear to have developed from those that do (Lutzoni et al. 2001). Although it is an involved process that is still being investigated, scientists do know that lichens have been on this earth for a very long time. A lichen fossil was discovered in Early Devonian Rhynie chert dating back 400 million years, indicating that lichens are certainly prehistoric organisms (Taylor et al. 1995)
Ramalina menziesii’s nearest relatives are those species of the Order Lecanorales and Family Ramalinaceae, of which there are 19, not including R. menziesii.
R. menziesii’s range runs along the Pacific Coast from southeast Alaska south to Baja California in Mexico, and extends only as far west as the Cascades, beyond which it is not found (see figure 1.)(McCune and Geiser 1997; Larson 1983). It grows between sea level and 3500 feet in elevation (Hale and Cole 1988).
|Figure 1. Distribution of Ramalina menziesii in California. Source: Hale & Cole 1988.|
No specific information is available regarding temperature and frost/precipitation ranges, but, as mentioned earlier, Ramalina menziesii is most prevalent on damp, coastal facing slopes, and is often absent from notably drier areas within its range (Hale and Cole 1988). The fact that it only occurs on the west coast of North America suggests a preference for a fairly temperate climate, and its restriction to coastal areas speaks to a need for periodic moisture as opposed to a continuously dry climate. McCune and Geiser (1997) write that for optimal health, most terrestrial lichens require climatic episodes that alternate from dry to wet. As such, it would appear that moisture and relatively mild temperatures are the limiting factors for this species. Given this species’ ability to capture particulate matter (and the associated nutrients) carried by the Westerly winds, a case could be made that these winds are also a limiting factor for Ramalina menziesii. Taken together, then, this species of lichen grows in the western coastal habitat of the U.S. and Mexico due to a combination of the winds, relatively temperate climate, and the fairly steady presence of moisture.
There is a paucity of information on R. menziesii’s origin and nativity; it is believed that only one percent of the fruticose and foliose lichen of California (two species) are endemic (this number could be higher for crustose lichen) but specific information as to the origin of this and other lichen of the Pacific Northwest is unavailable (Hale and Cole 1988). Figure 1 shows the counties of California in which R. menziesii is found, and its general location within each of these regions (Hale and Cole 1988).
Other interesting issues:
One of the unique qualities of lichens in general, is that they are very sensitive to atmospheric pollution. Given the ability of lichen to absorb nutrient and chemical material from wind and water, lichens can accumulate and be negatively impacted by, atmospheric toxins (Brodo et al. 2001). As such, lichens are a good tool by which to measure the air quality of a given region. Lichens are particularly sensitive to sulfur dioxide, but react to a whole host of pollutants including fluorides, hydrocarbons, lead, copper and zinc (Brodo et al. 2001). When either the photobiont or the alga is affected by the pollutant, the lichen becomes weak and dies (Brodo et al. 2001).
Not all lichens are as sensitive to air pollution as others. The genus Ramalina is one of the more pollution-sensitive lichen genera, as its filamentous nature provides a particularly large surface area through which airborne materials can be absorbed (Brodo et al. 2001).
Air pollution monitoring using lichens is particularly effective when the health of those located near a pollution source are compared over time to those farther away, in an area of less polluted air (Brodo et al. 2001). Not just a bellwether of poor air quality, lichens can also signal a reduction in atmospheric pollution. Lichen regeneration in a given area can testify to air quality improvements (Brodo et al. 2001).
Armstrong, W.P. 2001. Fruticose &Foliose Lichens. http://waynesword.palomar.edu/pljan98c.htm (last accessed November 9, 2003).
Boucher, V.L. and T.H. Nash III. 1990. “The Role of Fruticose Lichen R. menziesii in the Annual Turnover of Biomass and Macronutrients in a Blue Oak Woodland.” Botanical Gazette. Vol. 151 pp. 114-118.
Brodo, Irwin M.; Sylvia Duran Sharnoff; Stephen Sharnoff. 2001. Lichens of North America. New Haven: Yale University Press.
De Santis, Salvatore. 1999. “An Introduction to Lichens.” [On-line] http://www.nybg.org/bsci/lichens [October 8, 2003].
Hale, Mason E. Jr. and Mariette Cole. 1988. Lichens of California. Berkeley: University of California Press.
Larson, Douglas W. 1983. “Morphological Variation and Development in R. menziesii Tayl.” American Journal of Botany. Vol. 70 pp. 668-681.
Lutzoni, Francois; Mark Pagel; Valerie Reeb. 2001. Major fungal lineages are derived from lichen symbiotic ancestors. Nature. 411: 937-940.
McCune, B. and L. Geiser. 1997. Macrolichens of the Pacific Northwest. Corvallis: Oregon State University Press.
NatureServe Explorer. 2002. Plant/Animal Records. http://www.natureserve.org/explorer/species/index/Genus_RAMALINA_107731_1.htm (last accessed October 27, 2003).
Seaward, Mark R.D. ed. 1977. Lichen Ecology. Academic Press. San Francisco.
Senn-Irlet, Beatrice. nd. Moose, Pilze, Flechten: R. menziesii. http://sgiserv.unibe.ch/sgi/gallery/ramalina_menziesii.htm (last accessed November 9, 2003).
Sharnoff, Sylvia Duran (comp.). 2003. “Biographical Database of the Human Uses of Lichens.” [On-line]. http://www.lichen.com/biology.html [October 8, 2003].
Stromberg, Mark. (comp.) nd. Oak Woodlands: Lace Lichen. http://hastingreserve.org/oakstory/LaceLichen2.html (last accessed November 9, 2003).
Taylor, T.N. et al. 1995. The oldest fossil lichen. Nature. 378: 244.
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