ASCOMYCOTA | LECANOROMYCETES > LECANORALES > Cladoniaceae

Common name:             Glaucous Cladonia

Synonyms:                     -

Habitat:                           Heathland, upland moors

Substrata:                       Stumps, rotting wood, acid soil

Growth forms:               Lignicolous, terricolous                   

Basal thallus:                  Squamulose

Secondary thallus:         Podetia, erect, without cups

Apothecia:                     Rare

BLS identity rating:        Graded 3/5 (visually probable, but UV recommended)

Basal squamules very small, roundish to elongate, incised, greyish-green above, white below, but generally insignificant.

Podetia up to 50mm tall; simple and erect; mostly unbranched, although occasionally forked or even split into three, particularly towards the apices; pointed or with very narrow perforate cups; usually with a shallow, longitudinal, slit-like fissure around mid-height of the podetia, but often hard to distinguish; axils sometimes perforated in branched specimens; typically squamulose or roughly granular near the base often extending upwards, and then densely and finely sorediate in the upper part; pale greyish-green to brown, darker when wet, some specimens appearing very dark.

Cladonia glauca could be confused with other species, especially Cladonia subulata or sterile Cladonia macilenta, and possibly Cladonia rei, which is why subjecting to UV light is recommended - checking for UV+ vivid white, rather than UV- with C.subulata or UV+ pale blue with C.macilenta. In C.rei, the medulla reacts UV+ white, but the sorelia do not fluoresce. As my level of interest is a bit more casual, I shall rely on visual identification and be careful to separate any photos I'm not sure about. With regard to visual identification, it used to be said that Cladonia glauca could be distinguished from Cladonia subulata simply by confirming furrowing of the podetia, but that thinking is now considered unreliable as Cladonia subulata can also have a similar slit.

The species has widespread, but rather scattered distribution, seemingly more common in the northeast and eastern Scotland. In the south, it is mainly restricted to 'higher quality' habitats, typical of some of the New Forest heaths where it is mainly found on banks or tussocks in short-grazed areas or in hollow ways on burned heaths. Otherwise occurring on old rotting tree stumps.