Microsorum siamensis

Microsorum siamensis, commonly referred to as Siamese Fern or Siam Fern, is an attractive and hardy fern species within the Microsorum genus. This plant is native to Southeast Asia, particularly Thailand (formerly Siam), and is well-loved for its distinctive, lobed leaves and its ability to thrive in various indoor and outdoor environments, including aquariums and terrariums.

Morphological Characteristics:

• Leaves: The leaves of Microsorum siamensis are deeply lobed and can vary in shape from simple, undivided fronds to more complex, pinnate forms with multiple lobes or segments. The fronds typically measure 15-40 cm in length and 5-15 cm in width, depending on the growing conditions. The foliage is a vibrant green color with a slightly glossy surface, giving the plant a lush, tropical appearance. The leaves are leathery and tough, which helps the plant withstand various environmental conditions. The fronds emerge directly from a creeping rhizome, creating a dense, bushy appearance that is ideal for use in ground cover or as an accent plant in mixed arrangements.

• Stems and Rhizomes: The plant grows from a creeping rhizome that spreads horizontally just above or slightly below the soil surface. The rhizomes are typically dark brown to black and have a rough texture. They serve as the main growing point for the plant, from which the fronds emerge. The rhizomes can also produce roots that anchor the plant to various substrates, making Microsorum siamensis well-suited for growth in both soil and water-based environments.

• Growth Habit: Microsorum siamensis has a spreading, creeping growth habit, making it an excellent choice for ground cover or as an accent plant in mixed plantings. The plant’s ability to grow in a variety of substrates, including soil, rock, and even submerged in water, makes it highly versatile. It is often used in aquascaping, where it can be attached to driftwood or rocks in aquariums, as well as in terrariums and paludariums. The plant’s moderate growth rate allows it to fill out over time, creating a lush, green carpet or backdrop in various settings.

Ecological Preferences:

• Light: Microsorum siamensis thrives in low to medium indirect light but can tolerate a wide range of lighting conditions. In aquariums, it does well under low to moderate lighting, making it ideal for setups where more delicate plants may struggle. While it can tolerate brighter light, too much direct sunlight can cause the leaves to scorch, so it’s best to provide filtered or indirect light in outdoor or terrarium settings.

• Soil/Substrate: This fern prefers a well-draining, humus-rich soil mix when grown terrestrially. In aquariums, it can be attached to driftwood, rocks, or other decorations, as it does not require soil to grow when submerged. The rhizomes should not be buried completely in the substrate, as this can lead to rot. Instead, they should be allowed to rest on the surface or be lightly covered, ensuring that they remain aerated.

• Water: Microsorum siamensis enjoys consistent moisture, especially when grown terrestrially. The soil should be kept evenly moist but not waterlogged, as the plant is sensitive to root rot in overly wet conditions. When grown in aquariums, it should be submerged or partially submerged, where it will adapt to the aquatic environment. In both cases, good water quality and proper filtration are essential for maintaining the plant’s health.

• Humidity: This plant thrives in high humidity environments, ideally between 60-80%, making it well-suited for terrariums, paludariums, or humid indoor settings. While it can tolerate average indoor humidity, higher levels will promote healthier growth and prevent the edges of the leaves from browning. Regular misting or the use of a humidifier can help maintain optimal humidity in drier environments.

• Temperature: Microsorum siamensis prefers warm temperatures, ideally between 20-28°C (68-82°F). It can tolerate slight fluctuations in temperature, but consistent warmth will encourage the best growth. The plant is sensitive to cold and should be protected from temperatures below 15°C (59°F).

Additional Care Tips:

• Fertilization: When grown terrestrially, feed Microsorum siamensis with a balanced, water-soluble fertilizer every 4-6 weeks during the growing season. In aquariums, it can benefit from regular liquid fertilizer doses designed for aquatic plants. Avoid over-fertilizing, as this can lead to nutrient buildup and potential harm to the plant.

• Pest Management: Microsorum siamensis is generally resistant to pests but can occasionally attract common houseplant pests such as aphids or spider mites, particularly if grown in less-than-ideal conditions. Regular inspection and maintaining good air circulation will help prevent infestations. In aquariums, the plant is typically free from pests, though it’s important to ensure that any new additions to the tank are properly quarantined to avoid introducing unwanted pests or diseases.