Fascinating Lichens of Sri Lanka

Lecanora
Rim-lichens
Lecanorales Lecanoraceae
600
Lecanora is one of the most speciose lichen genera. It is cosmopolitan and
occurs from the tropics to the arctic. The species are found on various kinds of
substrates, such as bark, wood and rock. More rarely, they are found on soil or
moss, mostly in open areas.
The genus Lecanora includes a wide variety of growth forms and colours. It is
best circumscribed by its crustose habitat, Lecanora- type asci and simple spores.
Many species have lecanorine apothecia with prominent, thallus coloured
apothecial margins that form the rim of the discs. Apothecia and spores always
need to be examined under the microscope for the identification of the species
of this genus, together with the chemistry of the species using TLC.
Pannariaceae
Fo
R
Kroswia crystallifera
Description The thallus is foliose, thin, spreading and membranous. The lobes
are elongated, fan-shaped (flabellate), swells considerably when wet, and is
entirely composed of thread -like hyphae (homoiomerous) .The upper surface
is olive grey with white marbling, with bluish grey gymnidia (non-corticate isidia
that leave inconspicuous scars after falling off ) marginally . The lower surface is
veined and blackened towards the centre and with scattered tufts of blackish
rhizohyphae (single hyphae on the lower thallus surface for attachment).
Apothecia unknown in all the specimens collected in the world. This is a sterile
species, that is to say, it does not produce reproductive structures in its life cycle.
About 34 species have already been recorded in Sri Lanka. The three species
included here are new records for Sri Lanka which were recently recorded by
Weerakoon and Aptroot (2014). It is possible that more species exist in Sri Lanka,
as there are many gaps in relation to local lichen taxonomy.
Apothecia yellowish, green brown, or black, often pruinose, usually with
lecanorine margins the same colour and texture as the thallus (sometimes with
biatorine or rarely with lecideine), margins often contain calcium oxalate crystals;
Asci: Lecanora -type; Spores: simple and colourless.
Chemistry extremely variable. Atranorin or usnic acid or xanthones, and a wide
range of depsides, depsidones, terpenoids and fatty acids.
Lecanoraceae
Status A rare lichen in Sri Lanka that is restricted to specific habitats.
Habitat Mostly found in humid montane forests above 1400 m together with
mosses on tree trunks facing the sun.
Locations Horton Plains and a few places in Nuwara Eliya.
100 Fascinating Lichens of Sri Lanka
Fascinating Lichens of Sri Lanka 101