Whitewash Lichen

(Phlyctis argena)

Conservation Status
Whitewash Lichen
Photo by Luciearl
  IUCN Red List

not listed

 
  NatureServe

not listed

 
  Minnesota

not listed

 
           
           
           
           
 
Description
 
 

Whitewash Lichen is very common in Europe and North America. In the United States it occurs in the Pacific northwest and in the northeast from the East Coast to the Great Lakes region. It grows in very close contact with the substrate (crusticose) on the bark of oak and other deciduous trees, rarely on conifers, and rarely on rock. It neither harms nor benefits the tree.

The vegetative body may be thick or thin, small or large. It may appear as a small, well-defined patch with a distinct pale border, or as a large, irregular patch with diffuse pale edges, like a smear of paint. It consists of a central, vegetative portion containing both the algal and fungal partners (thallus), and a border with just the fungal partner (prothallus). The thallus is pale grayish-green or greenish white when fresh. It may be thin and smooth or thick, rough, and cracked. As it ages, the surface becomes gray and/or white, and it develops minute, pale green to bluish-green balls of cells (soredia). The soredia are fine, but they clump together forming coarse granules on the surface. When the thallus is thin the soredia are sparse. When the thallus is thick, the soredia are dense and cover the center. The structures that produce the soredia (soralia) are pale yellow to greenish-white, up to in diameter, and usually have a raised rim. As the lichen ages, the soralia erode, leaving just raised lines.

The thallus is surrounded by by a white, felt-like, and often conspicuous prothallus. The prothallus often forms a conspicuous white border about wide.

Disk-like, spore-producing structures (apothecia) are extremely uncommon. When present, they are minute, 1 64 to 3 64 (0.2 to 0.4 mm) in diameter, gray to black, and flush with the surface of the thallus, sometimes hidden by it.

 
     
 

Similar Species

 
 

Common Button Lichen (Buellia stillingiana) apothecia are very common, more abundant, and larger.

 
     
 
Ecology
 
 

Substrate

 
 

Trees

 
     
 

Growth Form

 
 

Crusticose

 
     
 

Habitat

 
 

Bark, rarely rock

 
     
 

Hosts

 
 

Oak and other deciduous trees, rarely conifers

 
     
 
Distribution
 
 

Distribution Map

 

Sources

4, 24, 26, 29, 30, 77, 81.

 
  1/29/2023      
         
 

Occurrence

 
 

 

 
         
 
Taxonomy
 
  Kingdom Fungi (fungi)  
  Subkingdom Dikarya  
  Phylum Ascomycota (sac fungi)  
  Subphylum Pezizomycotina  
  Class Lecanoromycetes (common lichens)  
  Subclass Ostropomycetidae  
 

Order

Ostropales  
 

Family

Phlyctidaceae  
 

Genus

Phlyctis (blemished lichens)  
  Mycobiont Phlyctis argena  
  Photobiont    
       
       
 

Synonyms

 
 

 

 
       
 

Common Names

 
 

Whitewash Lichen

 

 

 

 

 

 

 

Glossary

Apothecium

An open, disk-shaped or cup-shaped, reproductive structure, with spore sacs on the upper surface, that produces spores for the fungal partner of a lichen. Plural: apothecia.

 

Crusticose

Crusty; referring to lichens in such close contact with the rock surface (substrate) that it appears sprayed on like paint.

 

Prothallus

The border of a lichen where the fungal partner is growing but the algal partner is not. The color is different than the thallus due the absence of the algae.

 

Soredium

An asexual reproductive structure of a lichen in the form of a tiny dull granule on the thallus surface that can be easily brushed off. It consists of a cluster of algal cells (the photobiont) wrapped in fungal filaments (the mycobiont), but without an outer layer of protective tissue (cortex). Plural: soredia.

 

Thallus

The vegetative body of a lichen composed of both the alga and the fungus. Plural: thalli.

 
 
Visitor Photos
 
           
 

Share your photo of this fungus.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Attach one or more photos and, if you like, a caption.
 
 

Luciearl

 
    Whitewash Lichen   Whitewash Lichen  
           
    Whitewash Lichen   Whitewash Lichen  
           
 
MinnesotaSeasons.com Photos
 
 

 

 
           

 

Camera

     
 
Slideshows
 
  Phlyctis (Wallr.) Flot.
Olof Persson
 
  Phlyctis (Wallr.) Flot.  

 

slideshow

       
 
Visitor Videos
 
       
 

Share your video of this fungus.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Attach a video, a YouTube link, or a cloud storage link.
 
 

 

 
     
     
       
       
 
Other Videos
 
     
     
     

 

Camcorder

 
 
Visitor Sightings
 
           
 

Report a sighting of this fungus.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Be sure to include a location.
 
  Luciearl
January 2024

Location: Fairview Twp, Cass Co.

Whitewash Lichen  
  Luciearl
11/19/2018

Location: Fairview Township, Cass County

Whitewash Lichen  
           
 
MinnesotaSeasons.com Sightings
 
 

 

 

 

 

Binoculars


Created: 11/24/2019

Last Updated:

About Us | Privacy Policy | Contact Us | © MinnesotaSeasons.com. All rights reserved.