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Dot Lichen: A Diverse Group of Lichens

The term "Dot Lichen" serves as a common name for various lichens, most notably those belonging to the genera Arthonia and Micarea. Additionally, lichens within the genus Bacidia are referred to as "Dotted Lichens." These lichens are incredibly diverse, exhibiting a range of forms and colors and colonizing a variety of substrates.

Taxonomy and Nomenclature

• Group: Lichen
• Family: Arthoniaceae (for some Dot Lichens) and Icmadophilaceae (for Pink Dot Lichen) and Micareaceae (for Erratic Dot Lichen).
• Genera: Arthonia, Micarea, Bacidia, Dibaeis, Leptorhaphis, Mycobilimbia, Scoliciosporum
• Examples of Species and Common Names:
  • Arthonia arthonioides: Dot Lichen
  • Arthonia asteriscus: Dot Lichen
  • Dibaeis absoluta: Pink Dot Lichen
  • Mycobilimbia pilularis: 'Dot Lichen'
  • Bacidia rubella: Frosty-rimmed Dot Lichen
  • Leptorhaphis epidermidis: Birchbark Dot Lichen
  • Leptorhaphis atomaria: Birchbark Dot Lichen
  • Micarea globulosella: Globe Dot Lichen
  • Scoliciosporum chlorococcum: City Dot Lichen (Synonym: Bacidia chlorococca)
  • Micarea erratica: Erratic Dot Lichen
  • Arthonia exilis: Dispersed Dot Lichen
  • Arthonia tuckermaniana: Tuckerman’s Dot Lichen
  • Micarea nitschkeana: Nitschke’s Dot Lichen
  • Arthonia glebosa: Dot Lichen
• Synonyms/Alternative Scientific Names: Bacidia chlorococca (synonym for Scoliciosporum chlorococcum)

Distribution and Habitat

• Dot lichens can be found worldwide, including in areas such as New Orleans.
• They colonize diverse substrates, from rocks (including in Mt. Rainier National Park) and tree bark (including Palm trees in Florida) to birch bark and stone walls.

Morphological Characteristics

• Dot lichens are typically small, resembling dots or small patches on their substrate.
• Some, like Mycobilimbia pilularis, are crustose lichens with a grayish-green thallus and yellowy-brown apothecia.
• Dibaeis absoluta (Pink Dot Lichen) has pink apothecia born on very short stalks.
• Some species have a bright yellow color, described as "sulphur lichens" or "firedot lichens".

Quirky Facts

• Dot lichens can be easily overlooked, with some species going unnoticed even when abundant.
• One article headline exclaimed, "I'm lichen it!" in reference to eating oak moss.

Resources and Further Information

• Encyclopedia of Life
• Catalogue of Life
• USDA
• Smithsonian Institution, National Museum of Natural History, Department of Botany
• ResearchGate
• WikiSpecies