Identification notes
Formerly Preissia quadrata, this relatively robust thallose liverwort can be most easily recognised as belonging to the hepatic order Marchantiales by its complex-looking structures (receptacles) which bear reproductive structures or organs. If you are feeling adventurous, and your plants aren’t dirty, try the taste test – nibbling the thallus will produce a hot, peppery taste, although this can take a few seconds to kick in.
Little-known fact: Marchantia quadrata and related species also have two different types of rhizoid – broad smooth ones for anchoring the thalli and tuberculate ones for conducting water.
The compound pores on the surface of the thallus of M. quadrata (and M. polymorpha) are distinctive and even through a x 20 hand-lens can be seen to be cruciform (like a cross), and distinguish it from all other large thallose liverworts including Reboulia hemisphaerica which has circular pores.
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