Hammered Shield Lichen

(Parmelia sulcata)

Conservation Status
Hammered Shield Lichen
Photo by Luciearl
  IUCN Red List

not listed

 
  NatureServe

NNR - Unranked

 
  Minnesota

not listed

 
           
           
           
           
 
Description
 
 

Hammered Shield Lichen is a widespread, abundant, weedy lichen. It occurs across the northern hemisphere, in southern Africa, and in Australia. It is very common in Minnesota. It grows on the bark of deciduous and coniferous trees in relatively open habitats, disturbed sites, and agricultural lands. It also grows on mossy rock, but only rarely grows on soil.

The vegetative body (thallus) is leaf-like (foliose), greenish-gray to whitish-gray, more or less circular in outline, and divided into branches (lobes). The lobes are flat, 1 16 to 3 16 (2 to 5 mm) wide, widely spreading, overlapping, and touching but separate, not fused together. The tips are abruptly squared, as if cut off (truncate). The upper surface is shiny but sometimes has a white, flour-like or frost-like covering (pruinose). It has abundant powdery granules (soredia). It does not have shiny granules (isidia). It may be smooth but usually has a network of sharp ridges and depressions giving it a “hammered” appearance. This is the feature that gives the lichen its common name. It has minute, elongated, rounded openings (pseudocyphellae), and sometimes develops cracks along prominent pseudocyphellae. The lower thallus surface is black and is moderately to densely covered with black, unbranched root-like structures (rhizines). When wet, the thallus can usually be removed intact with a knife.

Hammered Shield Lichen rarely produces disk-like spore producing structures (apothecia). When present, they are 1 16 to 5 16 (2 to 8 mm) wide and have a dark brown disc.

 
     
 

Similar Species

 
     
     
 
Biology
 
 

Substrate

 
 

Trees

 
     
 

Growth Form

 
 

Foliose

 
     
 

Habitat

 
 

Open habitats, disturbed sites, and agricultural lands.

 
     
 

Hosts

 
 

Trees and mossy rock.

 
     
 
Use
 
 

Crottles are various lichens that were used to make dyes. Parmelia sulcata, sometimes called “Powdered Crottle”, was used as the source for a reddish-brown dye.

 
     
 
Distribution
 
 

Distribution Map

 

Sources

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

 
  5/30/2022      
         
 

Occurrence

 
 

Widespread and abundant

 
         
 
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

Parmelia (shield lichens)  
  Mycobiont Parmelia sulcata  
  Photobiont    
       
 

Synonyms

 
 

Parmotrema sulcata

Parmotrema sulcatum

 
       
 

Common Names

 
 

Cracked-shield Lichen

Furrowed Shield Lichen

Hammered Shield Lichen

Powdered Crottle

Powdered Shield

Shield Lichen

Waxpaper 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.

 

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

 
    Hammered Shield Lichen      
           
 
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  Luciearl
11/4/2019

Location: Superior Hiking Trail, Cook County

Hammered Shield Lichen  
           
 
MinnesotaSeasons.com Sightings
 
 

 

 

 

 

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Created: 11/25/2019

Last Updated:

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