Question

why are thallophytes called non-embryonic plants?

Answer 1

Thallophytes are also known as thallus plants as they have a simple plant body called thallus without any differentiation of root, stem or leaves.
These plants does not possess any embryonic stage in their life cycle i.e. embryo is not formed and zygote or fertilised egg either directly develop into a new plant or it does so through spore.