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Apothecia with a particular shape –
saddle-shaped apothecia
of
Peltigera
: in this genus the
apothecia are formed at the apex of lobes, and often resemble a saddle.
Apothecia with a particular shape – wart-like apothecia: the apothecia of most species of P
ertusaria
are immersed in thallus warts, that release the spores from a small apical pore. They can easily be
confused with perithecia, which however are usually not covered by a thallus layer containing the
photobiont.
STRUCTURES FOR VEGETATIVE REPRODUCTION
Lichens can also reproduce as a whole lichen symbiosis. This can be done by vegetative propagules
(isidia and soredia). When a lichen reproduces vegetatively, the organs of sexual reproduction are
generally lacking (but there are exceptions).
Isidia
: are protrusions from the upper surface of the thallus, covered by the cortex, which also
contain cells of the photobiont. They are detached from the base, and are rather 'heavy'. Isidia can
have different shapes (cylindrical, branched, flattened, granular etc.). In the following we provide
some examples.
Isidia of
Melanelia
.
