# Crustose Lichen (*Rhizoplaca polymorpha*)

Crustose lichens are tiny organisms that grow on rocks, trees, and even roofs. They come in different colors like gray, yellow, or orange and help keep the environment clean.

- **Category:** [Fungi](https://www.snappit.app/explore/categories/fungi)
- **Rarity:** Common
- **Danger:** 1/5 · Very low
- **Habitat:** Mountain regions, Deserts

![Crustose Lichen](https://commons.wikimedia.org/w/index.php?title=Special:Redirect/file/Rusty_crustose_lichens_%284503970687%29.jpg&width=800)

Photo: Jason Hollinger, CC BY 2.0 · [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Rusty_crustose_lichens_%284503970687%29.jpg)

## Appearance

The Crustose Lichen is a flat, paint-like growth that sticks very tightly to surfaces. It can be found in shades of grey, green, yellow, orange, or black, often forming intricate patterns. Unlike moss or other fungi, it appears as a thin, crusty layer fused to its substrate.

## Taxonomy

- **Kingdom:** Fungi
- **Phylum:** Ascomycota
- **Class:** Lecanoromycetes
- **Order:** Lecanorales
- **Family:** Lecanoraceae
- **Genus:** Rhizoplaca

## Interesting facts

- Crustose lichens are often among the first living things to grow on new volcanic rock.
- Lichens grow incredibly slowly; some only expand a tiny bit each year, making them hundreds of years old!
- Some lichens can survive being completely dried out for years, then come back to life with rain!
- Tiny water bears (tardigrades) often live safely hidden within the protective layers of lichens.

## Special abilities

- **Pioneer Power:** Crustose Lichen can colonize bare rock because its hardy nature helps it survive harsh, exposed environments as the first life.
- **Air Purifier:** Crustose Lichen has tiny pores that absorb nutrients and pollutants from the air, helping it clean the atmosphere while growing.
- **Rock Crusher:** Crustose Lichen can slowly break down rocks by secreting acids, which helps it extract minerals and creates new soil.

## Measurements & details

- **Height:** 0.1-0.5 cm
- **Edible:** inedible
- **Growth Substrate:** other
- **Season:** Year-round

## Ecological connections

- **Symbiotic with:** Green alga (*Trebouxia decolorans*) — Alga provides sugars through photosynthesis.
- **Eaten by:** Red slug (*Arion rufus*) — Slugs and snails graze on lichen surfaces.
- **Shelter:** Tardigrade (*Macrobiotus hufelandi*) — Tardigrades live protected within lichen tissues.

## Traits

- [Lichen](https://www.snappit.app/explore/traits/lichen): This trait describes a composite organism resulting from a symbiotic association between a fungus and a photosynthetic partner, typically an alga or cyanobacterium.
- [Nonvascular](https://www.snappit.app/explore/traits/nonvascular): This trait characterizes plants lacking specialized vascular tissues (xylem and phloem) for transporting water and nutrients.
- [Desert](https://www.snappit.app/explore/traits/desert): Desert habitats are arid regions characterized by extremely low precipitation and often extreme temperatures, supporting specialized flora and fauna.
- [Mountain](https://www.snappit.app/explore/traits/mountain): This habitat trait identifies species found in mountainous regions, characterized by high elevation, steep slopes, and varying climate zones.
- [Ancient Lineage](https://www.snappit.app/explore/traits/ancient-lineage): This trait signifies organisms belonging to a very old evolutionary group with ancestors dating back millions of years.

## Collections

- [Fungi](https://www.snappit.app/explore/collections/fungi)

## Safety

**Danger:** 1/5 · Very low

Enjoy looking at lichens but avoid touching them to keep them safe.

## Frequently Asked Questions

### How to identify Crustose Lichen?

Compare the cap shape, the underside, the stem and base, and whether the fungus grows on wood or soil. Some fungi have gills, others pores or teeth. A cap seen only from above often hides the most useful features. Mushroom Identifier: upload a photo and compare the visible details.

### How tall is Crustose Lichen?

0.1-0.5 cm

### Is Crustose Lichen edible?

inedible

### Where is Crustose Lichen usually found?

Mountain regions, Deserts

### What does Crustose Lichen grow on?

other

### When is Crustose Lichen in season?

Year-round

## More Fungi

- [Field Mushroom](https://www.snappit.app/explore/field-mushroom) (*Agaricus*)
- [Button Mushroom](https://www.snappit.app/explore/button-mushroom) (*Agaricus*)
- [Portobello Mushroom](https://www.snappit.app/explore/portobello-mushroom) (*Agaricus*)
- [Shiitake](https://www.snappit.app/explore/shiitake) (*Lentinula*)

---

Source: [Crustose Lichen: Facts & Places to See — Snappit](https://www.snappit.app/explore/crustose-lichen)