Metzgeriidae is a subclass found within the class of Jungermanniopsida and the species within are characterized as being “simple thalloid liverworts”. This subclass differs from Jungermanniidae such that most of its species have thallose body rather than having leaves.
These thalloid liverworts differ from those found in the class Marchantiopsida (complex thalloid liverworts) because of the lack of tissue differentiation within the thallus.
The gametophytes are typically small and the thalli are generally no more than one cell layer in thickness. Here are a few examples from different orders within this subclass: