Marvelous Macromitrium sullivantii: The Orthotrichaceae Epiphyte

Macromitrium sullivantii: The Marvelous Moss of the Orthotrichaceae Family

Introduction

Mosses may be small, but they play a big role in many ecosystems around the world. One particularly fascinating species is Macromitrium sullivantii Müll.Hal., a moss in the Orthotrichaceae

family. In this blog post, we’ll take a closer look at this marvelous little plant.

Background

Macromitrium sullivantii is a species of moss first described by German botanist Johann Karl August Müller in 1874. It belongs to the genus Macromitrium

, which contains over 400 species worldwide. The Orthotrichaceae is a large family of mosses known for their small size and tolerance of dry conditions.

Morphology and Identification

M. sullivantii forms small tufts or cushions, typically less than 1 cm tall. Its leaves are

lanceolate (lance-shaped) and have a strong midrib. The leaf margins are entire (smooth-edged). Capsules are ovoid and borne on short setae (stalks). A key identification feature is the hairy calyptra (hood) that covers the capsule.

Global Distribution and Habitat

This species is found in tropical and subtropical regions of the Americas, Africa, and Asia. It grows as an epiphyte on the bark of trees and shrubs in moist forests. In the United States, it occurs in Florida, Louisiana, and Texas.

Ecological Roles and Adaptations

Like other mosses, M. sullivantii plays important roles in its ecosystem:

• Helps retain moisture
• Provides habitat for micro-organisms
• Cycles nutrients
• Prevents soil erosion

It has several adaptations that allow it to thrive as an epiphyte:

• Absorbs water and nutrients directly through leaves
• Tolerates periods of desiccation
• Reproduces via spores dispersed by wind

Conclusion

Macromitrium sullivantii may be a small and inconspicuous moss, but it has a big ecological impact. Its ability to grow on trees in tropical and subtropical forests helps maintain moisture, cycle nutrients, and provide habitat for other organisms. Next time you’re in Florida or another habitat for this marvelous moss, see if you can spot its hairy calyptras on the trees! What other roles do you think small but mighty mosses play in their ecosystems?