Eastern Speckled Shield Lichen

(Punctelia bolliana)

Conservation Status
Eastern Speckled Shield Lichen
Photo by Luciearl
  IUCN Red List

not listed

 
  NatureServe

NNR - Unranked

 
  Minnesota

not listed

 
           
           
           
           
 
Description
 
 

Eastern Speckled Shield Lichen occurs across North America but is especially common in central United States. It is very common in Minnesota. It is found in open woodlands, fields, and roadsides. It grows on the bark of deciduous trees.

The vegetative body (thallus) is leaf-like (foliose), bluish-gray, and divided into branches (lobes). The lobes are small to medium-sized, mostly 1 16 to ¼ (2 to 6 mm) but up to (10 mm) in diameter. On older parts of the thallus, the lobes become wrinkled and folded and develop many small lobe-like growths (lobules) both on the edges and across the surface. The upper surface does not have powdery dull granules (soredia), shiny granules (isidia), or a chalky or “frosted” surface (pruina). However, it does have abundant, tiny, globular chambers (pycnidia) embedded in the thallus with an opening through which fungal spores are released. The pycnidia look like pale brown to black pinpricks on the thallus surface. This is the feature that gives the lichen its common name. The lower thallus surface is pale tan and is covered with pale unbranched anchoring structures (rhizines) up to the lobe edges.

Brown, slightly raised, disk-like, spore-producing structures (apothecia) are always present, usually abundant. The disks are broad, to (3 to 15 mm) in diameter, and are shaped like a plate with a ring around them. They are brown inside and the ring is made of tissue similar to the thallus. Larger disks often have a convoluted shape.

 
     
 

Similar Species

 
     
     
 
Biology
 
 

Substrate

 
 

Trees

 
     
 

Growth Form

 
 

Foliose

 
     
 

Habitat

 
 

Open woodlands, fields, and roadsides

 
     
 

Hosts

 
 

deciduous trees

 
     
 
Distribution
 
 

Distribution Map

 

Sources

4, 7, 24, 26, 29, 30, 77.

 
  5/29/2022      
         
 

Occurrence

 
 

Very common

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

Order

Lecanorales  
 

Suborder

Lecanorineae  
 

Family

Parmeliaceae (shield lichens and allies)  
  Subfamily Parmelioideae  
 

Genus

Punctelia (speckled shield lichens)  
  Mycobiont Punctelia bolliana  
  Photobiont Trebouxia ? (green algae)  
       
 

Synonyms

 
 

Parmelia bolliana

 
       
 

Common Names

 
 

Eastern Speckled Shield 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.

 

Foliose

Adjective: Leaf-like growth form; referring to lichens with leaf-like growths divided into lobes.
Noun: The leaf-like, vegetative body of a lichen (thallus) that has thin, flat lobes which are free from the substrate.

 

Isidium

The reproductive structure of a lichen consisting of a cluster of algal cells (the photobiont) wrapped in fungal filaments (the mycobiont) and enclosed within a layer of protective tissue (cortex). Plural: isidia.

 

Lobule

A small lobe-like subdivision of a lobe. In lichens, a small lobe-like, asexual, reproductive structure produced at the edge of a lobe, breaks off, and reestablishes elsewhere.

 

Rhizine

A root-like structure of a lichen that attaches the lower layer to the substrate.

 

Soredium

The reproductive structure of a lichen consisting of a cluster of algal cells (the photobiont) wrapped in fungal filaments (the mycobiont). Plural: soredia.

 

Thallus

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

 
 
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Luciearl

 
    Eastern Speckled Shield Lichen   Eastern Speckled Shield Lichen  
           
    Eastern Speckled Shield Lichen      
           
 
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  Luciearl
2/12/2019

Location: Cass County

Eastern Speckled Shield Lichen  
           
 
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Created: 2/15/2019

Last Updated:

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