Fruticose lichen

A fruticose lichen is a form of lichen fungi that is characterized by a coral-like shrubby or bushy growth structure. It is composed of a thallus and a holdfast. The lichen is formed from a symbiotic relationship of a photobiont such as cyanobacteria and twomycobionts such as fungus. Fruticose lichen is characterized by an ascending, bushy or pendulous appearance, and composed of a complex vegetation structure. While lichen communities are mainly controlled by water and light, vegetative dispersal and filamentous growth in fruticose lichen is often associated with areas of low elevation. Fruticose lichens can endure high degrees of desiccation. They grow very slowly and will often occur in extreme habitats such as on tree barks, on rock surfaces and on soils in the Arctic and mountain regions.

Fruticose lichen is a form of lichen composed of a shrubby or bushy thallus and a holdfast. The thallus is the vegetative body of a lichen that does not have true leaves, stems, or roots. Thallus colour of the lichen can be attributed to the amount of light in its environment. A light thallus color is associated with lower light conditions within the growing environment. Fruticose lichen is characterized by photobionts, the mode of vegetation dispersal, growth form and the substrate preference. The lichen's ability to survive extreme desiccation is due to its ability to quench excess light energy. Characteristic of fruticose lichen is the shape of the thallus. Like crustose lichen, fruticose lichen is composed of a holdfast which will act as an anchor for the lichen to grow in rock fissures, over loose sand or soil.

Fruticose or ‘shrubby’ lichen differ from other forms of lichen based on their bushy form that is attached to the ground only at the base of the lichen. The most important difference that distinguishes fruticose lichen from other forms of lichen is the continuous algal layer that grows around the circumference of the branches of the lichen. The thallus may be either rounded or flattened, unbranched or branched. Fruticose lichens have a fine, round, hair-like structures and are loosely attached to rocks and trees. Although fruticose lichens are defined as being bushy, they can also exhibit a flattened and strap-like appearance. Highly branched fruticose lichen have a high surface to volume ratio that results in a rapid drying and wetting pattern compared to lichens that have a lower surface to volume ratio.

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