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Lichen: Acarospora fuscata

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Name: Acarospora fuscata (Schrad.) Th.Fr.

Pronunciation: Acarospora fuscata

Conservation Evaluation: Least Concern

Acarospora fuscata showing the irregular areolate crazy paving patten. Note several apothecia per areole. © Paul Whelan.

Acarospora fuscata showing the irregular areolate crazy paving patten. Note several apothecia per areole. Photographed in Cork Harbour. © Paul Whelan.

Body Type: Crustose

Description: Thallus has the appearance of dried or encrusted cow dung because of the irregular areolate-squamulose crazy-paving pattern. Sometimes described as having a snakeskin look. Colour varies from dark oak brown to reddish brown to yellow brown. The areoles are angular with a variable gap between them; the edges may be upturned slightly revealing a dark underside (use 10x hand lens). The margins of the areoles are usually dark. The dark discs of the apothecia also have an angular appearance; often several are found on a single areole. They are either slightly sunken into an areole or are flush with its surface.

General view. Note the dark apothecia.  © Paul Whelan

General view. Note the dark apothecia. Photographed in Cork Harbour. © Paul Whelan

Chemical Tests: K-, KC+ red, C+ red, Pd-.

Nature Notes: A common lichen found typically on silica rich rocks such as the tops of walls or south facing ledges. It enjoys direct sunlight. Tolerant of nutrient rich areas and so is found near farms, on the tops of walls, at bird perches. Absent from limestone regions such as the Burren (apart from being found on silica-rich erratics in the Burren district). Not common in Ireland in graveyards where the majority of tombstones are made from limestone (or imported polished granite which is almost impossible for lichens to adhere to). Similar species is Acarospora impressula.

Vice County distribution map of Acarospora fuscata: See MapMAP-A-fuscata

Link: Map this species on the Lichen Survey

Other Acarospora recorded in Ireland

  • Acarospora benedarensis
  • Acarospora glaucocarpa (Ach.) Körb.
  • Acarospora heppii (Nägeli ex Hepp) Nägeli ex Körb.
  • Acarospora impressula Th.Fr.
  • Acarospora macrospora (Hepp) A.Massal. ex Bagl.
  • Acarospora rufescens (Ach.) Kremp.
  • Acarospora sinopica (Wahlenb.) Körb.
  • Acarospora smaragdula (Wahlenb.) A.Massal.
  • Acarospora veronensis Massal.

Text and images © Paul Whelan, 2009.