Origin and Common Names
Polymeridium pleiomerellum (Mull. Arg.) R. C. Harris is a species of lichen, which is a composite organism of a fungus and an alga or a cyanobacterium. It is commonly known as Wright's Kidney Lichen or Wright's Rock Shield Lichen. The plant can be found in North America, specifically in the Great Basin and Mojave Desert regions.
Appearance
Polymeridium pleiomerellum has a distinctive thallus (the vegetative part of a lichen) body that is kidney-shaped, lobed, and roughly wrinkled. The thallus is usually about 3-10 cm wide and has a gritty texture that is beige or grayish-green in color. The rhizines, which are root-like structures that anchor the lichen to its substrate, are black and club-shaped. The apothecia, the circular discs that contain the reproductive structures of the lichen, are rare, but when present, they are generally brownish-black in color and slightly raised.
Uses
Polymeridium pleiomerellum has low-level uses in traditional medicine, specifically in Native American remedies. Some indigenous peoples use it to remedy respiratory diseases, such as asthma and bronchitis, by brewing tea from the thallus body; however, it is not widely used in contemporary medicine. The lichen is also useful for lichenometry, a dating technique frequently used by geologists and archaeologists to determine the age of rocks and rock surfaces. Polymeridium pleiomerellum, in particular, has been used to date surfaces as young as 200 years and as old as 8,500 years.
Light Requirements
Polymeridium pleiomerellum requires moderate to bright light for optimal growth. It can tolerate some shade but will grow best in direct sunlight. It is important to avoid exposing the plant to prolonged periods of intense sunlight as this may cause leaf burn.
Temperature Requirements
Polymeridium pleiomerellum grows best in warm to hot temperatures. It requires a minimum temperature of about 60°F (15°C) and a maximum temperature of about 85°F (29°C) for optimal growth. Temperatures outside this range may slow down the growth of the plant or even cause damage to the leaves.
Soil Requirements
The soil requirements for Polymeridium pleiomerellum are slightly acidic to neutral soil with good drainage. The plant prefers rich, loamy soil that is slightly moist but not waterlogged. A potting mix that is specifically formulated for cacti or succulents works well for this plant. The use of a well-draining container is highly recommended to prevent waterlogging of the roots.
Cultivation methods for Polymeridium pleiomerellum
Polymeridium pleiomerellum requires bright, indirect light, and it does well in warm temperatures. It is best to grow this plant in an area with a temperature range of 65°F to 80°F (18°C to 27°C). This plant will also thrive in humidity levels that range from 40% to 60%. The plant can be planted in a potting mix that contains peat, perlite, and bark in equal percentages.
Watering needs for Polymeridium pleiomerellum
The Polymeridium pleiomerellum plant should be watered frequently to keep the soil moist but not waterlogged. It is best to allow the soil surface to dry out partially between watering sessions. Watering should be done in the mornings or evenings, and it should be done using lukewarm water. The water should have a pH level between 6 and 7.5.
Fertilization for Polymeridium pleiomerellum
Polymeridium pleiomerellum should be fertilized during the growing season, from spring to fall. A balanced, water-soluble fertilizer such as 20-20-20 should be used. The fertilizer should be applied at half strength every two weeks. It is best to apply the fertilizer during watering sessions to avoid over-fertilizing.
Pruning Polymeridium pleiomerellum
Polymeridium pleiomerellum requires minimal pruning. However, it is essential to remove any dead or discolored leaves as soon as they are spotted. Pruning can also be done to control the size and shape of the plant. It is best to use sharp, sterile pruning shears to avoid damaging the plant. The ideal time to prune the plant is during the growing season.
Propagation of Polymeridium pleiomerellum
Polymeridium pleiomerellum (Mull. Arg.) R. C. Harris commonly known as Pityopsis pleiomeris, is a perennial herbaceous plant found in North America. The plant can be propagated using various methods, including seeds, cuttings, and division.
Propagation through Seeds
The easiest and most common way to propagate Polymeridium pleiomerellum is through seeds. Collect mature seeds during fall and store them in a cool and dry place until spring. In spring, sow the seeds in soil that is moist and fertile. Keep the soil moist and the seeds will germinate in about two weeks.
Propagation through Cuttings
Another method of propagation is through cuttings. In late summer, take cuttings from the parent plant, making sure that the stem is healthy and free from any diseases. Cut the stem into sections of 4-6 inches and remove the lower leaves. Dip the cut end into rooting hormone powder and plant it in a well-draining soil mix. Water the cutting well and keep it in a warm and humid location. In about six weeks, the cutting will develop roots, and you can transplant it into a larger pot or the garden.
Propagation through Division
Polymeridium pleiomerellum can also be propagated through division. Divide the plant during spring or fall when it is not blooming. Dig up the root ball and separate it into two or more sections, making sure that each section has healthy roots and foliage. Replant the sections into a well-draining soil mix and water well. Keep the soil moist until the plant is established.
By using any of the above propagation methods, gardeners can create new Polymeridium pleiomerellum plants with ease.
Disease Management for Polymeridium pleiomerellum
Polymeridium pleiomerellum is generally a healthy species of plant that is resistant to most diseases. However, there are certain conditions that can trigger the onset of diseases that affect this plant. Here are some common diseases that affect Polymeridium pleiomerellum and ways to manage them.
Brown Spot
Brown spot is a fungal infection that causes the plant to develop brown spots on its leaves, which can lead to defoliation in severe cases. To manage this disease, remove any infected leaves and destroy them. Also, make sure to keep the plant well-watered but not overly moist. You can apply a fungicide to prevent the spread of the disease, especially during periods of high humidity.
Canker
Canker is a bacterial infection that causes the stems and branches of the plant to develop small, sunken lesions. The infected areas will eventually become dark and brittle, causing the branch to die-back. To manage this disease, remove all infected branches and dispose of them. Also, avoid pruning during wet conditions since this can spread the bacteria. Applying a copper-based fungicide to the affected areas can help prevent further spread of the bacteria.
Pest Management for Polymeridium pleiomerellum
Polymeridium pleiomerellum is generally free of serious pest infestation. However, some insects might target the plant. Here are some common insects that affect Polymeridium pleiomerellum and ways to manage their infestation.
Aphids
Aphids are tiny, often green insects that feed on the sap of plants. They can be found on the leaves and stems of the plant. To manage their infestation, you can wash them off using a blast of water or spray the plant with insecticidal soap. You can also introduce natural predators of the aphids like ladybugs or lacewings to control their population.
Spider Mites
Spider mites are tiny mites that can infest the plant, causing the leaves to turn yellow and brittle. To manage their infestation, you can wash them off the plant using a blast of water or regularly misting the plant. You can also apply insecticidal soap or a predatory mite-like Phytoseiulus persimilis to control their population.
