What kind of lichens are there

Their thalli may be upright, shrubby, or of pendulous strands. See Figure 3. Lichens can survive severe conditions because they can withstand drying. The lack of water interrupts photosynthesis. In this suspended state, some lichens are able to withstand great extremes in temperature.

The slow growth in lichens could possibly be attributed to their slow rate of photosynthesis since they are usually dry. A lichen absorbs most of its mineral nutrients from the air and rainfall.

Pollution in the atmosphere can be especially dangerous to lichens because they retain, and can accumulate, deadly amounts of heavy metals, sulfur, radioactive elements, NO 2 , and ozone.

Sulfur dioxide SO 2 is especially lethal to lichens because it lowers pH and deteriorates chlorophyll, which causes photosynthesis to cease. Anti-sulfur dioxide legislation in the last 25 years is allowing lichens to return to formerly polluted areas.

Lichens have been used to monitor the amount of pollutants in an environment. This is done by observing the condition of lichens as well as their chemical composition. Reproduction in lichens may be either sexual or vegetative asexual. In asexual reproduction, fragments of the thallus containing both the photobiont and the mycobiont separate and form into a new lichen. This may happen when a piece of the thallus is accidentally broken off, but specialized structures that have evolved in lichens, namely isidia and soredia , usually carry out this type of reproduction.

In most lichens undergoing sexual reproduction, tiny spores are produced within an ascus. Primordial landscapes, tangled branches, breathtaking wildlife and miles of woodland trails. From the countryside to cities, we care for thousands of woods throughout the UK, all free to visit. A dazzling array of shapes, sizes and colours. Find out about fungi and lichens, from ancient taboos to magic and medicine. Home to myth and legend, where folk tales began. It fuelled our ancestors and still houses thousands.

Ancient woodland has grown and adapted with native wildlife, yet what remains only covers 2. What is lichen? Seven types of lichen found on trees. Kylie Harrison Mellor.

Citizen science officer. What is a lichen? Where to see lichen You can see lichen in lots of places - with little blazes of colour cropping up on rocks, walls, twigs, bark and even on exposed soil surfaces.

The relationship between lichens and ancient woods and trees Ancient woodland is land that has been continually wooded for a very long time. Ramalina fastigiata Members of this genus are sometimes called strap or cartilage lichens because of those long strap-like branches. Ramalina farinacea Another strap-like species that is common throughout the UK. Xanthoria parietina This brilliantly coloured lichen is sometimes known as common orange lichen or yellow scale.

Physcia adscendens The pale grey, flattened branches of this lichen will hug the bark of trees tightly. Candelariella reflexa This lichen is made up of bright yellow to yellow-green granules and can appear fluffy. What can you spot in your local woodland? A lichen is an unusual organism because it consists of two unrelated organisms, an alga and a fungus. These two components exist together and behave as a single organism. When two organisms live together in this way, each providing some benefit to the other, they are known as symbionts.

The alga, because it is a green plant, can photosynthesize and provide energy for the lichen. The fungus contributes to the relationship by obtaining water and minerals and by protecting the algal cells from desiccation.

Together the fungus and the alga make up what is known as the lichen thallus. The color and growth form of the thallus is used to group and classify the lichens. The most common species of lichens on trees tend to be a gray-green color, but other species may be orange, yellow, slate blue, or black.

There are three major growth forms of lichens: foliose, fructicose, and crustose.