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Lichen: Caloplaca ceracea

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Name: Caloplaca ceracea J.R.Laundon

Caloplaca ceracea showing the off-white thallus lacking a clearly defined prothallus.

Caloplaca ceracea showing the off-white thallus lacking a clearly defined prothallus.

Caloplaca ceracea apothecia: note the large rim in the younger smaller apothecia and the narrower rim on the larger mature ones.

Caloplaca ceracea apothecia: note the large rim in the younger smaller apothecia and the narrower rim on the larger mature ones.

Pronunciation: Caloplaca ceracea

Conservation Evaluation: Least Concern

Body Type: Crustose

Description: The orange coloured apothecia are small, reaching a maximum size of just 1 mm. They frequently occur in clusters, although some may be scattered across the pale coloured thallus. A distinct prothallus is usually absent. It is easy to confuse it with Caloplaca crenularia so look carefully for the distinguishing features: C. ceracea apothecia look waxy when wet; the discs are orange-brown and pruinose. Apothecia have a layer of green algal cells under the disc; this can be seen if the apothecia is cut and viewed with a 20x hand lens or under a microscope. Ascospores are ellipsoid, 13-15 x 8 µm with a septum about a third the way up its length and 3-5 µm wide.  The disc is K positive purple or violet-red; the thallus is K negative. The tips of the paraphyses are a little swollen.

Caloplaca ceracea showing the apothecia in section. Note the green algal layer running under the apothecia. This distinguishes it from Caloplaca crenularia.

Caloplaca ceracea showing the apothecia in section. Note the green algal layer running under the apothecia. This distinguishes it from Caloplaca crenularia.

Chemical Tests: K+ crimson.

Nature Notes: Found on silica-rich coastal rocks in the mid to upper shore. It is rare inland.  Found on the West, North and North-West coast of Ireland. Caloplaca ceracea is rare on the south coast where this specimen was recorded and photographed.

Caloplaca ceracea spores.

Caloplaca ceracea spores.

Vice County distribution map of Caloplaca ceracea: See Map

Link: Map this species on the Lichen Survey

Other species recorded in Ireland:map-caloplaca-ceracea

  • Caloplaca alociza (A.Massal.) Mig.
  • Caloplaca arenaria (Pers.) Müll.Arg.
  • Caloplaca atroflava (Turner) Mong.
  • Caloplaca aurantia (Pers.) Hellb.
  • Caloplaca britannica R.Sant.
  • Caloplaca cerina (Ehrh. ex Hedw.) Th.Fr.
  • Caloplaca cerinella (Nyl.) Flagey
  • Caloplaca chalybaea (Fr.) Müll.Arg.
  • Caloplaca chlorina (Flot.) H.Olivier
  • Caloplaca cirrochroa (Ach.) Th.Fr.
  • Caloplaca citrina (Hoffm.) Th.Fr.
  • Caloplaca concilians (Nyl.) H.Olivier
  • Caloplaca crenularia (With.) J.R.Laundon
  • Caloplaca crenulatella (Nyl.) H.Olivier
  • Caloplaca dalmatica (A.Massal.) H.Olivier
  • Caloplaca decipiens (Arnold) Blomb. & Forssell
  • Caloplaca ferruginea (Huds.) Th.Fr.
  • Caloplaca flavescens (Huds.) J.R.Laundon
  • Caloplaca flavocitrina (Nyl.) H.Olivier
  • Caloplaca flavorubescens (Huds.) J.R.Laundon
  • Caloplaca flavovirescens (Wulfen) Dalla Torre & Sarnth.
  • Caloplaca holocarpa (Hoffm.) A.E.Wade
  • Caloplaca lactea (A.Massal.) Zahlbr.
  • Caloplaca littorea Tav.
  • Caloplaca luteoalba (Turner) Th.Fr.
  • Caloplaca marina (Wedd.) Zahlbr. ex Du Rietz
  • Caloplaca maritima de Lesd.
  • Caloplaca microthallina (Wedd.) Zahlbr.
  • Caloplaca obliterans (Nyl.) Blomb. & Forssell
  • Caloplaca obscurella (Lahm ex Körb.) Th.Fr.
  • Caloplaca ochracea (Schaer.) Flagey
  • Caloplaca polycarpa (A.Massal.) Zahlbr.
  • Caloplaca saxicola (Hoffm.) Nordin
  • Caloplaca teicholyta (Ach.) J.Steiner
  • Caloplaca thallincola (Wedd.) Du Rietz
  • Caloplaca ulcerosa Coppins & P James
  • Caloplaca variabilis (Pers.) Müll.Arg.
  • Caloplaca verruculifera (Vain.) Zahlbr.

Text & Images Copyright Paul Whelan, 2008: