| TAXON: | Kuettlingeria ceracea (J.R. Laundon) P.F. Cannon & Coppins (2024) |
| RECENT SYNONYMS: | Caloplaca ceracea J.R. Laundon (1992) |
| FAMILY: | Teloschistaceae |
| GROWTH FORM: | Crustose, heteromerous |
| SUBSTRATES: | Siliceous rock, particularly washed by brackish seepage |
| PHOTOBIONT: | Trebouxioid alga |
| REPRODUCTION: | Apothecia, pyncidia |
| ASCUS: | Elongate-clavate; apex Teloschistes-type; 8 spores |
| SPORES: | Ascospores ellipsoidal, polarilocular, 13-15 × ~8 µm, septum 3-5 µm; conidia bacilliform to subglobose |
| NOTABLE FEATURES: | Thallus pale- to dark-grey, thin, epilithic, rimose-areolate; apothecia lecideine; exciple orange, swollen, sometimes flexuose; disc orange, sometimes with yellowish tinge; algal layer underneath hypothecium |
| CHEMICAL TESTS: | Apothecia K+ purple (anthraquinones) |
| HABITAT: | Rocky shores from xeric-supralittoral zone (upper splash zone or ‘grey zone’) to terrestrial halophilic zone (lower inland zone affected by salt spray) |
| DISTRIBUTION: | Widespread on rocky shores, especially in northern and western Britain |
| CONSERVATION STATUS: | Least Concern |
| LICHENICOLOUS FUNGI: | Lichenodiplis lecanorae, Muellerella lichenicola |
| IDENTIFICATION DIFFICULTY: | Green 2: Field identification possible with care |
| CONFUSION SPECIES: | Blastenia crenularia |
FIELD NOTES
Kuettlingeria ceracea has a distinctive appearance and a fairly narrow habitat, so it’s natural to suspect that you’ve encountered it when you see something like it. But you mustn’t rely on outward appearances, especially at first glance. It’s exceedingly easy to confuse K. ceracea with the look-alike Blastenia crenularia, which is found in similar habitats, and indeed often just nearby.
Morphologically, the apothecia of each lichen appears subtly different. Those of K. ceracea tend to be more matt and even yellowish, with a brighter orange exciple. Those of B. crenularia tend to be glossier, with a brighter brick-red hue. But these distinctions can be hard to discern clearly, especially if you’re not familiar with either species.
Chemical testing doesn’t help. Thallus spot-tests are negative, and the discs of both lichens react K+ purple. Fortunately, however, there are some simple tests that you can perform in the field to separate the two species. The tests seek to reveal whether there exists an algal layer underneath the apothecium: present for K. ceracea, but absent for B. crenularia.
Some field lichenologists advise wetting the apothecia to see if a greenish tinge appears through the discs. I personally find this method less reliable, or at least harder to be sure of. Instead, I prefer ‘field dissection’: section an apothecium cleanly with a razor-blade or very sharp knife, and use a hand-lens to observe whether an algal layer is present. Both methods are illustrated below.
LAB NOTES
Kuettlingeria ceracea can normally be identified without microscopy.
SPECIMENS
Kuettlingeria ceracea : Scotland : VC98 Argyll : NR7993 : August 2024 : On siliceous outcrop : First record for hectad
Kuettlingeria ceracea : Scotland : VC101 Kintyre : NR6974 : August 2024 : On siliceous outcrop
Kuettlingeria ceracea : Scotland : VC101 Kintyre : NR7074 : August 2023 : On siliceous outcrop
