Lichen: Xanthoria calcicola
Name: Xanthoria calcicola Oxner (1937)

Xanthoria calcicola on mortar. Feeding snails have worn down the isidia towards the centre of the patch.
Pronunciation: Xanthoria calcicola
Conservation Evaluation: Least Concern
Body Type: Foliose
Description: Overall it looks similar to the common Xanthoria parietina, but is larger (20 cm) with wider lobes. The principle distinguishing point is the presence of large convex isidia towards the centre of the thallus. Apothecia are rare, and when present the jagged rim is the same colour as the deep-orange-brown thallus. The underside is white with simple rhizines.
Chemical Tests: K+ crimson.
Nature Notes: Found in coastal areas of Ireland on mortar and in other calcareous situations such as brickwork. It has been found on acid bark, but this is a rarity and may eventually be recognised as a habitat variety.
Vice county distribution map: See Map
Link: Map this species on the Lichen Survey
Other species recorded in Ireland:
Xanthoria candelaria (L.) Th.Fr.
Xanthoria ectaneoides (Nyl.) Zahlbr.
Xanthoria elegans (Link) Th.Fr.
Xanthoria parietina (L.) Th.Fr.
Xanthoria polycarpa (Hoffm.) Th.Fr. ex Rieber
Xanthoria ulophyllodes Räsänen
Text and images © Paul Whelan, 2009.

