Dimorphic lichens


Ascomycota > Lecanoromycetes > Lecanorales > Cladoniaceae.
Cladonia is a common lichen with about 28 species found in Queensland.
They grow on soil, rock, among moss and occasionally on dead wood.

The thallus is characteristically composed of greenish, leaf-like squamules which may
    be permanent or disappear when podetia form.
They are from 0.5 to 6 mm long and up to 2 mm wide and lack a cortex underneath.
They may be round, wedge-shaped, lancinate or lobed and the edge may be smooth, lobed or incised.
The margins may or may not have soredia on them.

Podetia are another characteristic feature of Cladonia.
They are stem-like structures that arise from the basal squamules and are usually toped by apothecia
    and/or pycnidia although some are sterile.
Often only 0.5 to 10 mm they can be as tall as 6 cm and up to 3 mm in diameter.
They may be simple or branch near the top; cylindrical or tapering; pale, dark or greyish-green
    and sometimes brown.
They may have tiny squamules on the sides, mainly at the base and the upper part may have a granular
    appearance due to soredia.

A scyphus (scyphi) is defined either as as a cup-like podetium or restricted to the cup-like
    structure on the top of some podetia.
It may have apotheca or pycnidia on its rim.
It is characteristic of Cladonia although not present in all species.

The cup is often about 2 to 6 mm wide but sometimes up to 10 mm.
It may be irregular in shape and have a smooth or finely toothed margin.
A ring of scyphi may form around its margin, or from its centre, and these in turn may grow
    and form more tiers of scyphi.
The scyphi may have squamules on the sides.
They may also carry tiny (up to 0.3mm), brown or black, pycnidia on their rims.
Asexual spores are produced in the pycnidia.

Apotheca, or fruit-bodies, are present in many, but not all species of Cladonia.
They sit on top of a cylindrical podetium or on the rim of a cup-like scyphus.
They are convex, up to 2 mm in diameter and red or a pale, dark, or reddish-brown.