Hammered Shield Lichen

(Parmelia sulcata)

Conservation Status

IUCN Red List

not listed

NatureServe

NNR - Unranked

Minnesota

not listed

 
Hammered Shield Lichen
Photo by Luciearl
 
Description

Hammered Shield Lichen is a widespread, abundant, weedy lichen. It is one of the most common lichens worldwide. 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

 
Ecology

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.

Unlike most lichens, Hammered Shield Lichen is tolerant of air pollution. It is often used as an indicator of air quality in natural areas.

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 (shield lichens, sunburst lichens, rosette lichens, and allies)

Order

Lecanorales (shield lichens, rim lichens, and allies)

Suborder

Lecanorineae

Family

Parmeliaceae (shield lichens and allies)

Subfamily

Parmelioideae (typical shield lichens)

Genus

Parmelia (shield lichens)

Mycobiont

Parmelia sulcata

Photobiont

 

   

Subordinate Taxa

 

   

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

An asexual reproductive structure of a lichen in the form of a tiny outgrowth of the upper cortex. It consists of a cluster of algal cells (the photobiont) wrapped in fungal filaments (the mycobiont), and a shiny outer layer of protective tissue (cortex). Plural: isidia.

 

Rhizine

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

 

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.

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Luciearl

Hammered Shield Lichen  

Hammered Shield Lichen

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Luciearl
2/20/2024

Location: Baxter, Crow Wing County

Hammered Shield Lichen

Luciearl
11/4/2019

Location: Superior Hiking Trail, Cook County

Hammered Shield Lichen
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Created: 11/25/2019

Last Updated:

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