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Lichen: Dermatocarpon miniatum

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General View

Name: Dermatocarpon miniatum (L.) W.Mann (1825)Perithecia

Pronunciation: Dermatocarpon miniatum

Conservation Evaluation: Least Concern

Body Type: FoliosePerithecia view

Description: The thallus is a single lobe attached to the substrate by a single holdfast. The lobe varies in size from 10 mm to 75 mm. Readily grows in a circular pattern. The lobes are frequently incised giving a multi-lobed appearance. The surface has a whitish powdery or pruinose appearance. The colour of the thallus itself varies considerably from a reddish-brown to grey to dark brown. Dark brown spots cover the surface. These are the openings from the reproductive perithecia.map-dermatocarpon-miniatum

The lower surface lacks rhizines but may show small blisters or ridges. The colour ranges from almost black to leather-brown. Photobiont is a green algae. Lobes are concave and incised. Thallus: 20 mm – 70 mm diam. 0.2 mm to 0.7 mm thick. Perithecia 0.2 mm to 0.3 mm diam. No algae or paraphyses are present in the perithecia. Spores are colourless and single celled, ellipsoidal and are packed at 8 per ascus.

Chemical Tests: All reactions negative.

Nature Notes: Common in the West of Ireland, particularly on the calcareous rocks of the Burren. Frequently found on rocky seashores and around lakes on siliceous rocks exposed to spray or irregular flooding such as water flowing off a rock after rain. Reproduces by fragmentation where bits of the thallus break off and lodge in rock crevices. Rare above 500 m. A similar species is Dermatocarpon intestiniforme, which is multi-lobed.

Vice County distribution map of Dermatocarpon miniatum: See Map

Link: Map this species on the Lichen Survey

Other speccies recorded in Ireland

  • Dermatocarpon intestiniforme (Körber) Hasse
  • Dermatocarpon leptophyllodes (Nyl.) Zahlbr.
  • Dermatocarpon luridum (With.) J.R.Laundon
  • Dermatocarpon meiophyllizum Vain.

Text and images © Paul Whelan, 2009.