Lecanora.
Ascomycota > Lecanorales > Lecanoraceae.
There are about 300 species of Lecanora of which 73 occur in Australia living on trees, soil or rocks.
About 50 species in Queensland.
Microscopy and chemical tests are necessary for identification.
They are crust lichens and most species have algal cells in the apothecal rim making it the same colour as the thallus.
The thallus may be crustose in the centre but lobed at the edge, granular or areolate.
When visible, the prothallus (fungal hyphae only) at the margin may be white, greyish, or blackish-brown.
There are no isidia but soredia are sometimes present.
The roughly circular apotheca may be on the surface, sometimes with a constricted base or in the stroma.
The discs are various colours and the margin is usually the same colour as the thallus but some species have
a small or no visible rim.
Lecanora helva.
A crustose lichen with an indistinct margin and a surface that may be continuous or areolate.
The marginal prothallus is brown with black or blue tints.
Colours range from yellowish, white, grey or green.
There are whitish-grey soredia in soralia.
The apotheca, up to 1mm, are sessile although they may be partly in the stroma when young.
The thick or thin rim is the same colour as the thallus.
The flat discs are orange or pale to yellow-brown.
The epihymenium is red-brown to orange-brown.
There are similar species that need microscopy and chemistry to differentiate them.
J.F.
