• Caloplaca arnoldii (Wedd.) Zahlbr. ex Ginzb.

There are no records for this species at present.

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This species forms neat non-pruinose, deep orange crustose rosettes with lobed edges (12cm diam.) which like a good red wine may take many years to reach this mature colour from its yellow-orange, more youthful, shade. It grows clamped to the substratum except for a tiny area close to the tip of the lobes. It occupies well-illuminated siliceous rocks near the coast so cannot be mistaken for C. saxicola, which is a calcicole. It is scattered in Ireland.

Key characteristics

  • An acidophile; it forms small, deep orange crustose rosettes except at the margins which are lobed
  • Young thalli are yellow-orange.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Caloplaca arnoldii (Wedd.) Zahlbr. ex Ginzb.. [In] LichenIreland. Accessed on 2018-08-17.