Parmotrema.
Ascomycota > Lecanoromycetes > Lecanorales > Family Parmeliaceae.
Foliose lichens up to 30 cm across growing on bark, trees or rock.
The surface may be smooth or wrinkled, shiny or dull and may become finely cracked with age.
The upper surface can be grey, ashy white, greenish, greyish-green or rarely yellowish-green.
When dry the lobes are grey and shrivelled but they can rehydrate.
The flat, soft or leathery lobes can be up to 20 mm wide.
They may be round, somewhat irregular or elongated (up to 10 mm long and 2 mm wide).
They may be separate or overlap slightly.
The lobe tips are round but become toothed or scalloped with age.
Some have white spots or blotches (maculae) where the photobiont is missing.
Black marginal cilia, simple or branched and up to 4 mm long may be sparse or conspicuous.
They are absent in some species.
There are usually no pruina.
Isidia, soredia and apotheca may be present or absent.
Isidia can be on the lobe edges or the surface, be simple or branched and sparse or dense.
Some have brown tips and there are often cilia on the tips.
Soredia may be marginal or laminar.
Apothecia are common in some species and rare in others.
They can be up to 14 mm across and have a brown disc.
The lower surface has a central black area with scattered, usually simple, rhizines.
The margins are brown, smooth or slightly wrinkled and have no rhizines.
Parmotrema tinctorium.
A foliose lichen growing on trees and rocks.
The thallus, up to 30 cm across, is loosely adherent.
It has a pale grey or green-grey upper surface which is smooth peripherally but dull centrally.
The lobes are wide being 10 – 20 mm across and have round apices and smooth or lobed margins.
There are no cilia or soredia.
Isidia may be few to dense, initially central but later on the edges as well.
They may be simple, branched, cylindrical or with enlarged brown tips.
Apothecia are very rare.
The lower surface has a wide, smooth brown margin around a central area which is black
and has scattered, short rhizines up to 2 mm long.
Parmotrema perlatum.
A foliose lichen, up to 15 – 20 cm across, which grows on bark and occasionally rocks.
The upper surface of the lobes is smooth, grey or greenish-grey and there may be blackened areas.
The lobes are flat, up to 15 mm wide, with round apices and a scalloped margin.
The marginal cilia are sparse, black and up to 2-4 mm long.
Soredia are common and are in soralia on, or near, the lobe margins.
There are no isidia and apotheca are rare.
The lower surface has a smooth, brown margin around a central black area with simple rhizines.
J.F.
