North America Native Plant

Macmillan’s Fontinalis Moss

Botanical name: Fontinalis macmillanii

USDA symbol: FOMA3

Habit: nonvascular

Native status: Native to North America  

Macmillan’s Fontinalis Moss: A Rare Native Aquatic Treasure Have you ever wondered about the tiny, often-overlooked plants that quietly thrive in our waterways? Meet Macmillan’s fontinalis moss (Fontinalis macmillanii), a delicate aquatic bryophyte that’s both fascinating and incredibly rare. This native North American moss might not catch your eye like ...

Rare plant alert!

Region: Conservation status by state

Status: S1S2: Status is uncertain but is somewhere between the following rankings: Critically Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 5 or fewer occurrences or very few remaining individuals (<1,000) ⚘ Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘

Macmillan’s Fontinalis Moss: A Rare Native Aquatic Treasure

Have you ever wondered about the tiny, often-overlooked plants that quietly thrive in our waterways? Meet Macmillan’s fontinalis moss (Fontinalis macmillanii), a delicate aquatic bryophyte that’s both fascinating and incredibly rare. This native North American moss might not catch your eye like a showy wildflower, but it plays an important role in aquatic ecosystems and deserves our attention and protection.

What Exactly Is Macmillan’s Fontinalis Moss?

Macmillan’s fontinalis moss belongs to a group of plants called bryophytes, which includes mosses, liverworts, and hornworts. Unlike the plants you’re probably more familiar with, mosses don’t have true roots, stems, or leaves in the traditional sense. Instead, they’re simple, herbaceous plants that often attach themselves to solid surfaces like rocks, logs, or other underwater structures rather than growing in soil.

This particular moss is aquatic, meaning it spends its life submerged or partially submerged in water. It forms delicate, branching patterns that can create beautiful underwater gardens when conditions are just right.

Where Does It Call Home?

Fontinalis macmillanii is native to North America, though specific details about its geographic range remain somewhat mysterious. This uncertainty partly stems from the moss’s rarity and the specialized expertise needed to identify different Fontinalis species accurately.

A Rare Gem Worth Protecting

Here’s where things get serious: Macmillan’s fontinalis moss has a Global Conservation Status of S1S2, which places it in the rare to imperiled category. This means populations are either very small, highly vulnerable, or both. In the world of conservation, this is a red flag that demands our attention and respect.

If you’re lucky enough to encounter this moss in the wild, consider yourself privileged to witness something truly special. However, this rarity status comes with responsibility.

Should You Try to Grow It?

Given its rare status, we need to approach Macmillan’s fontinalis moss with extra care. While native plants are generally wonderful additions to appropriate gardens, rare species require special consideration:

  • Never collect this moss from wild populations
  • Only consider cultivation if you can source it from reputable, conservation-minded suppliers
  • Ensure you can provide the specific aquatic conditions it needs
  • Consider this moss only if you’re creating habitat for conservation purposes

For most gardeners interested in aquatic mosses, it’s better to choose more common native aquatic plants that can provide similar ecological benefits without putting rare species at risk.

Benefits to Your Aquatic Garden

While we can’t recommend widespread cultivation due to its rarity, understanding the potential benefits helps us appreciate why protecting this species matters:

  • Provides shelter and habitat for small aquatic creatures
  • Helps filter and clean water naturally
  • Adds delicate, natural beauty to water features
  • Supports biodiversity in aquatic ecosystems

How to Identify Macmillan’s Fontinalis Moss

If you’re exploring aquatic environments, you might wonder if you’ve stumbled upon this rare moss. Identification of Fontinalis species can be quite challenging and often requires microscopic examination by experts. Generally, Fontinalis mosses:

  • Grow attached to submerged rocks, logs, or other hard surfaces
  • Form branching, feathery patterns
  • Appear as small, delicate green growths underwater
  • Are usually found in clean, flowing water

If you suspect you’ve found something special, photograph it in place and contact local botanists or conservation groups rather than disturbing it.

The Bigger Picture

Macmillan’s fontinalis moss reminds us that not all garden-worthy plants are appropriate for cultivation. Sometimes, the best way to appreciate a species is to protect its wild habitat and admire it from a respectful distance. By understanding and respecting rare species like this moss, we become better stewards of our native plant communities.

For those interested in aquatic gardening with native plants, consider exploring more common native aquatic mosses and other water plants that can provide similar benefits without conservation concerns. Your local native plant society or extension office can help guide you toward appropriate alternatives that will thrive in your specific region.

Macmillan’s Fontinalis Moss

Classification

Group

Moss

Kingdom

Plantae - Plants

Subkingdom
Superdivision
Division

Bryophyta - Mosses

Subdivision

Musci

Class

Bryopsida - True mosses

Subclass

Bryidae

Order

Isobryales

Family

Fontinalaceae Schimp.

Genus

Fontinalis Hedw. - fontinalis moss

Species

Fontinalis macmillanii Cardot - Macmillan's fontinalis moss

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA