ASCOMYCOTA | LECANOROMYCETES > LECANORALES > Cladoniaceae

Common name:             Gnome Fingers or Nipple Lichen

Synonyms:                     Cladonia papillaria

Habitat:                           Heathland, primarily wet heath

Substrata:                       Acid peat and humous, very acid soils

Growth forms:               Terricolous                          

Basal thallus:                  Crustose

Secondary thallus:         Podetia, 'tooth-like'

Apothecia:                     Lecideine, rare, dark red-brown fruits

BLS identity rating:        Graded 1/5 (identification should be straightforward)

Basal thallus forming a persistent, often wide-spreading crust of greyish-white or cream-coloured contiguous granules.

Podetia can be frequent; concolourous, but often with a pale green tinge when wet; typically, short and stubby, normally around 5mm tall, but sometimes up to 15mm or even 20mm; barrel or tooth-like, hollow and very fragile; usually simple in form, but often branched or coralloid in well-developed specimens; generally smooth or with scattered rounded granules.

Apothecia rare but, where present, dark red-brown; pycnidia frequent, medium to dark brown, visible as tiny ostioles on the branch tips.

Pycnothelia papillaria is a declining species, both here in Britain and in lowland Europe. It is still found in the Scottish Highlands, some upland moors and a few southern heaths, but very rarely in between. The exception is the New Forest where it is still quite abundant in some areas. It is said to be one of the most tolerant heathland lichens in respect of trampling, whether by humans or livestock and, consequently, survives on the edges of paths. It is however, very much dependent on light, so only flourishes in areas that are heavily grazed, routinely burned or generally disturbed to maintain open conditions.

It is mainly found on firm, acid peat or partially compacted humous in unshaded, damp to seasonally wet, rather than permanently waterlogged, areas of heathland; also, on very acid soils or shallow humous over rock; and often alongside or close to species such as Cladonia strepsilis which favour similar habitats.