Origin and Common Names
Pertusaria globularis (Ach.) Tuck. is a lichen species that belongs to the family of Pertusariaceae. The plant is commonly known as 'button lichen' or 'rock shield lichen'. It is found in different parts of the world, including Europe, North Africa, Asia, and North America.General Appearance
Pertusaria globularis has a unique, tough, and leathery appearance that is easily recognizable. It often grows in circular or irregular patches on rocks, dry soil, or old wood. The plant is characterized by numerous tiny discs that resemble buttons, which are usually greyish-brown or olive-green in color. The discs grow up to 3mm in diameter and sit on a thallus that has irregularly shaped lobes. The thallus of Pertusaria globularis is thick and ranges from a yellowish-orange to greenish-grey color. The lobes are usually small and less than 5mm wide, with a marginal soralia that produces powdery soredia. The plant can sometimes be mistaken for a fungus, but it is a lichen that grows slowly over decades or even centuries, reaching up to 5cm in diameter.Uses
Pertusaria globularis has been used in the past for several medicinal purposes, particularly by indigenous communities in North America. It was believed to have healing properties and was applied externally to treat skin infections, wounds, and sores. Today, Pertusaria globularis is mainly used as an indicator of environmental pollution. The plant's sensitivity to air quality and heavy metal pollution has made it a valuable tool for environmental monitoring. Scientists also use the plant in various research studies because of its unique properties and biological activity. In conclusion, Pertusaria globularis (Ach.) Tuck. is a fascinating lichen species that has been used for centuries for different purposes. Its unique appearance, slow growth, and sensitivity to environmental factors make it a valuable plant for scientific research and monitoring.Light Requirements
Pertusaria globularis is an epiphytic species and therefore requires indirect or filtered light to grow. The plant does not perform well in direct sunlight as it can cause damage to the thallus.
Temperature Requirements
The species is mostly found in temperate climates and can tolerate fluctuations in temperature. It grows best in moderate to cool temperatures ranging from 10°C to 25°C. Higher temperatures can cause the thallus to dry out, while lower temperatures can slow down the growth rate.
Soil Requirements
Pertusaria globularis does not grow in soil as it is an epiphytic species. It mainly grows on bark, twigs, and leaves of trees, typically in humid environments. The presence of organic matter and moisture is essential for the plant to thrive. It can also grow on rocks and walls, as long as the conditions are suitable for its survival.
Cultivation Methods
Pertusaria globularis can be propagated through the use of vegetative cuttings, provided that the fragments contain thallus, which is the body of the plant. The plant requires a moderate temperature of around 20-22°C, in addition to a humid environment and a moderately lighted location. The plant is not very demanding when it comes to soil, but it requires good aeration and drainage, which means that a porous and well-draining substrate should be used.
Watering Needs
The plant does not need a lot of water after establishment, as it can go for a long time without irrigation. Watering should be scheduled according to how the substrate dries out, as the plant prefers to remain dry. During hot weather, it is essential to irrigate the surface of the plant to keep it from drying out entirely. However, the plant must never be waterlogged, as this encourages fungal growth, which may lead to rotting.
Fertilization
Pertusaria globularis thrives well without the need for regular fertilization, as the lichen has a unique mechanism to extract nutrients from the atmosphere in addition to photosynthesis. However, if the growth rate of the plant is too slow, moderate fertilization with a balanced fertilizer can be applied to stimulate growth. Care should be taken to avoid using excess fertilizer, as it can lead to the death of the plant.
Pruning
There is no need for substantial pruning in Pertusaria globularis as it has an indefinite growth habit. However, removing any dead or yellowing parts of the plant will help redirect the plant's energy towards new growth. Care should be taken not to damage or disturb the thallus, as this can cause the plant to lose its anchorage and lead to its death.
Propagation of Pertusaria globularis
Pertusaria globularis is a lichen species that reproduces vegetatively through fragmentation and asexually through soredia and isidia. Fragmentation occurs when parts of the thallus break off and develop into new individuals. On the other hand, soredia and isidia are small propagules that detach from the thallus and grow into new lichen
Propagation through Fragmentation
Fragmentation is a natural process that occurs in lichens when parts of the thallus break off. When this happens, the separated parts can grow into new individuals under favorable environmental conditions. Fragmentation is an easy method of propagation that does not require any special treatments. All you need to do is identify healthy individuals, carefully detach parts of the thallus and provide the right growing conditions for the new fragments.
Propagation through Soredia
Soredia are small propagules that form on the upper surface of the lichen thallus. They consist of a mass of intertwined fungal hyphae and green algal or cyanobacterial cells. When detached from the thallus, soredia can grow into new lichen individuals under favorable conditions. To propagate Pertusaria globularis through soredia, you need to identify healthy individuals with mature soredia, remove a few soredia and scatter them on a suitable substrate. Moist and shady environments are best for soredia growth, and it may take several weeks or months for the soredia to establish and grow into new lichen individuals.
Propagation through Isidia
Isidia are small outgrowths that protrude from the lichen thallus. They consist of a mass of intertwined fungal and algal or cyanobacterial cells covered by a thick layer of cortical tissue. Isidia detach from the thallus and grow into new lichens when they come into contact with a suitable substrate. Isidia production is not as common as soredia production, but they are useful in lichen propagation. To propagate Pertusaria globularis through isidia, you need to identify individuals with mature isidia, detach a few isidia and scatter them on a suitable substrate. Moist and shady environments are also best for isidia growth, and it may take several weeks or months for the isidia to establish and grow into new lichen individuals.
Disease and Pest Management for Pertusaria globularis
Pertusaria globularis is a lichen species that has been observed to be affected by several pests and diseases. Vermin, fungi, bacteria, and viruses are the major pests that commonly affect the growth and survival of this plant species.
Pest Management
Vermin: Vermin such as slugs, snails, and caterpillars can consume the leaves of Pertusaria globularis, which can lead to a decline in plant health. The easiest way to manage vermin is to pick them off by hand. Applying diatomaceous earth or other natural insecticides to the plants can also deter pests from feeding on the leaves.
Fungi: Fungi such as powdery mildew can appear on the leaves of Pertusaria globularis. Regular inspection of plants to detect early signs of infection is necessary to reduce the spread of fungi. Fungicides like copper, neem oil, or potassium bicarbonate can help prevent the spread of powdery mildew on plants.
Bacteria: Bacterial infections such as bacterial leaf spots can also damage Pertusaria globularis. To prevent the spread of bacteria, detaching any infected leaves, and disposing of them in the trash is necessary. Applying copper spray or bactericides at regular intervals can help reduce the risk of bacterial infections occurring on plants.
Viruses: While viruses are not as common in Pertusaria globularis, they can still potentially affect the plant. Viral infections usually result in mottled leaves or stunted growth and cannot be treated, so prevention is the key to reducing the impact of viral infections. Maintaining a clean growing environment, avoiding using contaminated tools on this plant, and removing any infected plants can help prevent this type of infection from spreading.
Disease Management
Root Rot: Overwatering can cause root rot in Pertusaria globularis. To prevent root rot, only water the plant when the top inch of soil is dry. If root rot occurs, remove the infected soil, allow the wounds to air dry, and replant in fresh soil.
Environmental Stress: Pertusaria globularis can suffer under extreme weather conditions. Drought and excessive heat can cause leaf drop and stunted growth. Providing protection from the elements and maintaining adequate moisture levels can help ensure the plant stays healthy.
Maintenance: Proper pruning is also crucial in managing diseases in Pertusaria globularis. Removing old and damaged parts of the plant regularly can prevent diseases from spreading. Make sure to disinfect the pruning tools before use to avoid contamination.
By being vigilant and taking preventative measures, gardeners can effectively manage pests and diseases in Pertusaria globularis.
