Origin
Myelochroa aurulenta, also known as Xanthoparmelia aurulenta, is a foliose lichen that primarily grows in North America, particularly in the United States. It can be found in various habitats, including forests, deserts, and alpine areas.
Common Names
The common names for Myelochroa aurulenta include gold dust lichen, golden shield lichen, and sulfur dust lichen. These names come from the lichen's distinct yellow/golden coloration and its powdery texture.
Uses
Myelochroa aurulenta is often used as an indicator of air quality due to its sensitivity to atmospheric pollutants. It has also been used as a traditional medicine by some Native American tribes to treat various ailments such as respiratory infections and stomach disorders. However, the lichen's potential medicinal properties have not been extensively studied.
General Appearance
Myelochroa aurulenta has a distinctive yellow/golden coloration, but it can appear darker or brownish in certain lighting conditions. It has a foliose thallus, meaning it has leaf-like lobes that are densely clustered together and can range in size from a few millimeters to several centimeters. The lobes are typically flat and slightly curled along the edges, and the underside is usually pale in color with tiny black dots. The lichen produces apothecia, which are small, cup-shaped structures that contain spores.
Light Requirements
Myelochroa aurulenta grows best in areas with bright, indirect light. Direct sunlight can be harmful and may cause leaf scorching. Therefore, it is best to provide filtered light or place the plant in a shaded area where it can receive partial sun exposure.
Temperature Requirements
This plant prefers moderate temperatures ranging from 60-75°F (15-24°C). It can tolerate slightly cooler temperatures, but below 50°F (10°C), the growth rate may slow down considerably. Extreme heat or cold can also damage the leaves and may stunt the overall growth of the plant.
Soil Requirements
Myelochroa aurulenta prefers soil that is well-draining and rich in organic matter. A pH range of 5.5 to 7.0 is ideal for this plant. It can tolerate slightly acidic or slightly alkaline soil, but extreme levels either way can stunt the plant’s growth. Moreover, the presence of peat moss and perlite in the soil can improve drainage and aeration, which will aid the plant’s growth.
Cultivation methods
Myelochroa aurulenta requires cool, moist conditions to grow, making it suitable for cultivation in shaded areas with high humidity levels. The plants can be grown both in soil and on rocks, commonly found in mountainous areas.
Watering needs
These plants require frequent watering to maintain their hydration levels, however, the soil should not be waterlogged. Watering should be done in the morning to allow enough time for the plants to dry out before nightfall as excessive moisture could attract pests and disease.
Fertilization
Myelochroa aurulenta is not a heavy feeder, but occasional fertilization can be beneficial in promoting healthy growth. Fertilizers with high nitrogen content should be avoided as they can encourage the growth of competing plants such as mosses.
Pruning
Pruning is not necessary for Myelochroa aurulenta as they have a slow growth rate. However, if trimming is necessary, it should be done during the plant’s dormant period to avoid damaging new growth. Dead or damaged branches and leaves can be removed anytime throughout the year.
Propagation of Myelochroa aurulenta
Myelochroa aurulenta, commonly known as gold dust lichen, can be propagated through either sexual or asexual methods.
Sexual Propagation
Sexual propagation of Myelochroa aurulenta involves the use of spores. Spores are tiny cells produced by the reproductive structures of the lichen and are dispersed by wind. For successful propagation, it is important to collect clean and healthy spores. The spores can be collected by placing a healthy lichen thallus in a paper bag and leaving it in a dry, warm place until the spores are released. The spores can then be cultured on a suitable growth medium to facilitate the germination process.
Asexual Propagation
Asexual propagation of Myelochroa aurulenta can be carried out by several methods, including fragmentation, soredia, and isidia.
Fragmentation involves breaking off a thallus and planting it in a new location. This method works best with healthy thalli that have well-developed attachment structures.
Soredia are small, dust-like particles that contain both algal and fungal cells. These can be found on the surface of the thallus and can be easily dispersed by wind or rain. To propagate the lichen using soredia, simply sprinkle them onto a suitable substrate and ensure they are kept moist until they establish.
Isidia are small, raised projections that also contain both algal and fungal cells. They are similar to soredia but are typically larger and less powdery. To propagate the lichen using isidia, simply detach them from the thallus and plant them in a suitable location.
Disease Management for Myelochroa aurulenta
Myelochroa aurulenta is a relatively disease-resistant plant. However, some common diseases that might affect the plant include:
- Lichen spot disease: This disease manifests itself in the form of small, circular spots on the plant's surface. It is caused by fungal pathogens that can be managed through the use of copper-based fungicides.
- Anthracnose disease: This disease causes yellowing of the leaves followed by defoliation. It is caused by fungal pathogens that can be managed through the use of fungicides containing propiconazole or mancozeb.
- Phoma blight: This disease causes brown spots on the leaves and is caused by the fungal pathogen Phoma. It can be managed through the application of fungicides containing mancozeb or copper-based fungicides.
To prevent the occurrence of diseases, it is crucial to ensure proper sanitation in the garden. Always ensure that you remove and dispose of any infected plant material around the plant. Additionally, ensure that the plant is growing in well-draining soil, receiving sufficient light, and is not overwatered.
Pest Management for Myelochroa aurulenta
Common pests that might affect Myelochroa aurulenta include:
- Aphids: These insects suck sap from the leaves of the plant, leading to yellowing and wilting of the leaves. It is advisable to use insecticidal soap or neem oil to get rid of the pests.
- Spider mites: These pests cause damage to the leaves, resulting in yellowing and bronze-like discoloration. They can be controlled through the use of insecticidal soap or horticultural oil.
- Thrips: Thrips cause damage to the leaves and petals of the plant, resulting in discoloration and distortion. They can be managed through the use of insecticidal soap or neem oil.
To prevent pest infestations on the plant, ensure that you maintain proper garden hygiene. It is crucial to remove and dispose of any fallen plant debris and avoid overwatering. Additionally, ensure that the plant is growing in well-draining soil and is receiving sufficient light.
