Overview
Thelidium papulare (Fr.) Arnold, also known as "wart lichen," is a type of foliose lichen that belongs to the family Pilocarpaceae. It can be found growing on rocks and tree barks in temperate regions.
Description
The wart lichen has a distinct appearance, with its flat lobes ranging from light green to pale yellow or gray in color. The lobes have a raised, wart-like texture, which gives the lichen its common name. The underside of the lobes is typically dark brown to black.
Range and Habitat
Thelidium papulare can be found in various countries throughout the world including North America, Europe, and Asia. It grows on rocks, tree barks, and sometimes on soil, in temperate regions.
Uses
The wart lichen doesn't have any known uses in terms of medicine or nutrition, but it is often used as an indicator of air pollution. Since lichens are highly sensitive to environmental pollution, the presence or absence of Thelidium papulare in an area can help determine the level of air pollution present in that location.
The wart lichen is also occasionally used as a decorative element in gardens or as a biological indicator of air quality in urban settings. It can be a good way to monitor air quality in an area, especially in urban environments where air pollution is a constant concern.
Light requirements
Thelidium papulare typically grows in shaded or partially shaded areas. It prefers diffused light and is not adapted to direct sunlight exposure. The plant can grow in open areas, provided there is a cover of other vegetation acting as shade.
Temperature requirements
The optimal temperature for the growth of Thelidium papulare is between 10 and 20°C. Although it can tolerate temperatures as low as 0°C, prolonged exposure to frost can be detrimental to its growth. High temperatures, above 30°C, can also have negative effects and lead to dehydration and plant death.
Soil requirements
Thelidium papulare prefers moist, well-drained soils with a neutral to acidic pH. The plant can grow in a variety of soil types, including loamy, sandy, or clay soils, as long as there is sufficient drainage. Excessive moisture or waterlogged soils can lead to root rot and inhibit growth. The presence of organic matter in the soil can be beneficial for the plant's growth and development.
Cultivation methods
Thelidium papulare is a terrestrial lichen species that can grow on various types of soil and rocks. It can tolerate extreme temperatures, making it adaptable to different environments. To cultivate this plant, a substrate such as a mixture of soil, sand, and peat is suitable.
The container should have adequate drainage holes to prevent overwatering. The best time to plant Thelidium papulare is during the spring and fall months. The lichen should be placed in a location with indirect sunlight and low air pollution levels.
Watering needs
Thelidium papulare is a drought-tolerant lichen, meaning it can survive with minimal water. As a result, overwatering can result in waterlogging and fungal growth. Watering this lichen every 2-3 weeks is sufficient in most cases. The watering should be done at the base of the plant, and no water should be splashed on the leaves to avoid fungal growth.
Fertilization
Since Thelidium papulare is a lichen species, it doesn't require traditional fertilization. Instead, this plant obtains nutrients through photosynthesis and obtains minerals from the substrate it's grown in. However, it can benefit from organic matter like compost or mulch, which adds nutrients to the substrate over time.
Pruning
Pruning Thelidium papulare is not necessary since it doesn't grow stems or branches. This plant develops in a circular shape and can be removed altogether by gently uprooting and transplanting it somewhere else. In cases where it overgrows and negatively affects other plants, scissors can be used to trim off the edges of the lichen.
Propagation of Thelidium papulare (Fr.) Arnold
Thelidium papulare is a lichen that mainly grows on rocks, and it reproduces both sexually and asexually. Here are the plant's propagation methods:
Soredia
Soredia are the most common method of asexual reproduction in Thelidium papulare. Soredia are small, powdery, and can be found on the surface of the thallus. They are made up of both fungal hyphae and algal cells. When soredia gets dispersed, they land on suitable surfaces and start to grow into new plants.
Gemmae
Gemmae are specialized structures that form on the thallus of Thelidium papulare. They are tiny, multicellular structures that can grow into new plants when conditions are favorable. Gemmae are often produced when the plant is growing in moist environments, and they get detached from the parent thallus and start a new life cycle.
Sexual Reproduction
While asexual reproduction in Thelidium papulare is more common, the plant can also reproduce sexually. Sexual reproduction occurs when reproductive structures known as ascocarps develop on the thallus. The ascocarps protect the ascospores, which get released into the air when the ascocarp gets mature. These spores then land on suitable surfaces and start to grow into new plants after forming new thalli.
Disease Management
Thelidium papulare is susceptible to various diseases that can cause severe damage to the plant. To manage these diseases, it is essential to maintain good cultural practices such as watering, fertilization, and pruning. The following are the common diseases that might affect the plant and ways to manage them:
1. Anthracnose
Anthracnose is a fungal disease that causes leaf spots, blights, and cankers. The best way to manage anthracnose is to prune infected branches and leaves, clean up debris, and avoid overhead watering. In severe cases, you can use a fungicide according to the manufacturer's instructions.
2. Powdery mildew
Powdery mildew is a fungal disease that causes a white powdery growth on leaves, stems, and flowers. To manage powdery mildew, you can spray the plant with a mixture of baking soda and water or neem oil. You can also improve air circulation around the plant by pruning and thinning out branches.
Pest Management
Thelidium papulare is also vulnerable to pest attacks. The following are the common pests and ways to manage them:
1. Scale insects
Scale insects are small, oval-shaped insects that feed on sap from the plant, causing yellowing leaves, stunted growth, and weak branches. You can manage scale insects by using insecticidal soap or horticultural oil. You can also remove the insects by hand using a soft brush and warm, soapy water.
2. Spider mites
Spider mites are tiny pests that feed on the plant, causing bronzing leaves and webbing on the undersides of the leaves. To manage spider mites, you can spray the plant with water to reduce the population. You can also use insecticidal soap or neem oil. In severe cases, you can use a miticide according to the manufacturer's instructions.
By following these disease and pest management strategies, you can keep your Thelidium papulare healthy and thriving. It is also recommended to regularly monitor the plant for any signs of diseases or pests and take immediate action to prevent further damage.
