Microlejeunea erectifolia: The Tiny Moss with a Big Story
Introduction
Have you ever stopped to admire the tiny, delicate mosses growing on trees and rocks? One particularly fascinating species is Microlejeunea erectifolia (Spruce) Steph., a diminutive moss with an outsized ecological importance. In this blog post, we’ll dive into the world of this captivating bryophyte and explore what makes it so special.
Background
Microlejeunea erectifolia is a species of leafy liverwort moss in the family Lejeuneaceae. The Lejeuneaceae are the largest family of liverworts, containing over 1000 species found worldwide, mostly in tropical regions. The genus Microlejeunea
contains some of the smallest members of the family.
Morphology and Identification
M. erectifolia forms minuscule mats on tree bark, leaves, and other substrates. The individual plants are among the smallest of all mosses, with shoots typically less than
3 mm long. The leaves are only 0.2-0.4 mm long and are arranged in two rows. Under magnification, oil bodies can be seen in the leaf cells, a characteristic feature of the Lejeuneaceae family. Identifying M. erectifolia requires patience and a keen eye. The leaves are ovate with a pointed tip and have an inflated lobule at the base. The underleaves are small and bifid (split in two at the tip). Sporophytes are rarely produced.
Global Distribution and Habitat
Microlejeunea erectifolia has a pantropical distribution, found in tropical regions around the world including Central and South America, Africa, and Asia. It grows in moist, shady habitats in lowland to montane forests, typically as an epiphyte on tree bark and leaves but sometimes on rocks. This tiny moss is an indicator of high quality, undisturbed tropical forests. Its presence signifies a healthy, humid microclimate that many other moisture-loving organisms also depend on.
M. erectifolia has several adaptations for life in the tropical forest canopy:
Small size: Being tiny reduces desiccation risk and allows growth on small substrates.
Lobules: The inflated leaf lobules help retain moisture.
Asexual reproduction: Most populations spread by fragmentation rather than spores, an adaptation to the epiphytic lifestyle where spores may get lost.
Conclusion
Microlejeunea erectifolia may be small, but it is a crucial component of tropical forest ecosystems worldwide. Next time you are in a tropical forest, take a moment to search for this minuscule moss and appreciate the outsized role it plays. What other secrets might the miniature world of mosses hold?
