ASCOMYCOTA | LECANOROMYCETES > PELTIGERALES > Peltigeraceae

Genus Peltigera, meaning 'carrying a light shield' - from the shape of the type apothecia but,

collectively, members of the genus are commonly referred to as Pelt Lichens.

Common name:            -

Synonyms:                    Peltigera spuria

Habitat:                         Disturbed ground, such as alongside tracks (otherwise as text)                    

Substrata:                     Various sandy to loamy, or stony soils

Growth form:                Terricolous (often with moss associations)                             

Thallus type:                  Foliose

Apothecia:                    Lecanorine, 'finger-shaped'

BLS identity rating:        Graded 2/5 (visual identification possible with care)

Thallus small, fresh growth often with just a few lobes showing that are more or less immersed in the ground, later forming compact rosettes to around 3cm, at most 5cm, across; when young, the lobes have a 'mouse-ear' shaped appearance; later with up-curved margins, when better described as 'clam-shell-like', the lobes growing to about 2cm long by 1cm wide, and becoming markedly ascending as the thallus matures and becomes fertile.

Upper surface finely felty with grey-white tomentose especially towards the margins; younger specimens easily distinguishable from other related species as they are more or less covered with laminal soralia containing coarse grey soredia, but which disappears at maturity when the apothecia start to grow.

Colour grey to greyish-brown, turning olive green when moist.

Underside whitish with prominent cream to pale brownish reticulate veins with conspicuous, virtually hair-free, spaces between.  

Rhizines simple at first, then thickening out and becoming somewhat 'bottle-brush' shaped, growing to around 2.5mm long, usually sparse around the margins, but more crowded towards the centre.

Apothecia isolated or in small clusters towards the lobe margins, erect and 'finger-shaped' once mature, with delicately crenulate and denticulate margins; reddish-brown, later brown-chestnut.

In my area, the effect of turning olive green when moist as a result having a green, rather than blue-green algal layer, is only shared (in similar habitat) with Peltigera hymenina and Peltigera neckeri, both of which have a glossy rather than felty surface so easily distinguishable.

Peltigera didactyla is a widespread, but scattered species, being rather scarce if some areas, but locally abundant in others. In the New Forest the species has mostly been recorded from recently disturbed ground alongside tracks and within the heathland burn-cycle areas, but also from the somewhat unique lichen-rich rough grass area at Blandford, which is the site of an old sandpit that was infilled with washed waste sand and then sown with grass seed back in 1992. Elsewhere, it could be found on earth banks, roadsides, urban wasteland and in quarries.

NB. this 'species account' and accompanying photos will be regularly reviewed, refined and/or amended as further samples are found and inspected - I believe the details are correct, but I'm also mindful that, in some cases, the source information varies, even to the point of being slightly contradictory, so I want to ensure the page is as accurate as possible.