North America Native Plant

Riccia Macallisteri

Botanical name: Riccia macallisteri

USDA symbol: RIMA8

Habit: nonvascular

Native status: Native to North America  

Discovering Riccia macallisteri: A Tiny Native Liverwort Worth Knowing Meet Riccia macallisteri, one of North America’s lesser-known botanical treasures. This tiny liverwort might not make headlines like showy wildflowers or towering trees, but it plays a fascinating role in our native ecosystems and can add unique character to specialized garden ...

Rare plant alert!

Region: Conservation status by state

Status: S2S4: Status is uncertain but is somewhere between the following rankings: 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) ⚘ Apparently Secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the state or more than 10,000 individuals ⚘

Discovering Riccia macallisteri: A Tiny Native Liverwort Worth Knowing

Meet Riccia macallisteri, one of North America’s lesser-known botanical treasures. This tiny liverwort might not make headlines like showy wildflowers or towering trees, but it plays a fascinating role in our native ecosystems and can add unique character to specialized garden spaces.

What Exactly Is a Liverwort?

Before we dive into the specifics of Riccia macallisteri, let’s clear up what we’re talking about. Liverworts are small, non-flowering plants that belong to a group called bryophytes, along with their cousins the mosses and hornworts. Think of them as some of the earth’s most ancient land plants – they’ve been around for hundreds of millions of years!

Unlike the plants you’re probably more familiar with, liverworts don’t have true roots, stems, or leaves. Instead, Riccia macallisteri forms flat, ribbon-like structures called thalli that spread across surfaces like tiny green carpets.

Where You’ll Find This Native Beauty

Riccia macallisteri is native to North America, though its exact distribution range isn’t fully documented in readily available sources. Like many liverworts, it tends to prefer quiet, undisturbed spots where it can establish its delicate colonies without competition from larger plants.

A Conservation Concern Worth Attention

Here’s something important to know: Riccia macallisteri has a Global Conservation Status of S2S4, indicating it may be uncommon to fairly common across its range. While this doesn’t put it in immediate danger, it’s a reminder that our smaller native plants deserve attention and protection too.

Spotting Riccia macallisteri in the Wild

Identifying this liverwort takes a keen eye and perhaps a magnifying glass! Here’s what to look for:

  • Small, flat, green ribbons or lobes that branch into a Y-shape
  • Thalli (the plant body) that are typically less than an inch long
  • A tendency to grow in small colonies or mats
  • Preference for moist, shaded areas often on soil or rock surfaces
  • Absence of the leaf-like structures you’d see on mosses

Is Riccia macallisteri Good for Gardens?

While you won’t find Riccia macallisteri at your local garden center, it can be beneficial in naturalistic garden settings. Here’s why you might want to welcome it:

  • It helps prevent soil erosion on gentle slopes and disturbed areas
  • Creates habitat for tiny invertebrates and soil organisms
  • Adds authentic native character to rock gardens and naturalized spaces
  • Requires no maintenance once established in suitable conditions
  • Contributes to the complex web of native plant communities

Creating Conditions Liverworts Love

If you’re interested in encouraging native bryophytes like Riccia macallisteri in your landscape, focus on creating the right environment rather than trying to plant them directly:

  • Maintain areas with consistent moisture but good drainage
  • Provide partial to full shade
  • Minimize soil disturbance in potential habitat areas
  • Avoid using pesticides or fertilizers in bryophyte-friendly zones
  • Consider creating rock gardens or stone pathways where liverworts might naturally establish

The Bigger Picture

Riccia macallisteri might be small, but it represents something important in native gardening: the value of our complete native plant communities, not just the showiest members. By learning to recognize and appreciate plants like this tiny liverwort, we become better stewards of our local ecosystems.

While you probably won’t be actively planting Riccia macallisteri, knowing it exists and understanding its role helps you make more informed decisions about creating truly native, ecologically valuable garden spaces. Sometimes the smallest plants teach us the biggest lessons about the intricate beauty of our natural world.

Riccia Macallisteri

Classification

Group

Liverwort

Kingdom

Plantae - Plants

Subkingdom
Superdivision
Division

Hepaticophyta - Liverworts

Subdivision

Hepaticae

Class

Hepaticopsida

Subclass

Marchantiae

Order

Marchantiales

Family

Ricciaceae Rchb.

Genus

Riccia L., nom. cons.

Species

Riccia macallisteri M. Howe

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