Lichens

A hand holds up a large clump of white, branching lichen. — A ranger holds up a clump of "Tree Coral" lichen (Sphaerophorus globosus) that fell off a tree during a wind storm. Take a closer look at fallen lichen like this, but then please return it back to where you found it. Clumps like this are still alive and are an important part of a healthy forest.
NPS Photo

Drawings of several different lichen types, labeled Foliose, Crustose, and Fruticose. — Lichens can be distinguished by their growth form, which can fall into three main groups: Foliose, Fruticose, and Crustose.
NPS/C. Vecchio

What is a lichen?

Lichens are a symbiotic relationship between algae, fungus and yeast. There are over 500 different species of lichen in Mount Rainier National Park. Advances in DNA testing have necessitated a number of changes to lichen taxonomy. The names given here are current as of January 2020.

Lichens generally can be grouped by growth form, including foliose, fruticose, and crustose forms, as described in the sections below. Some species are a blend of two forms.

A special vocabulary is used when discussing lichen structure. The main body of the lichen is referred to as its thallus, and the fruiting bodies are called apothecia (singular: apothecium).

Lichens of Mount Rainier
Foliose Lichens

Learn about Foliose lichens, which are leaf-like.
Lichens of Mount Rainier
Fruticose Lichens

Learn about Fruticose lichens, which have a three-dimensional structure.
Lichens of Mount Rainier
Crustose Lichens

Learn about Crustose lichens, which adhere tightly to their substrate.