Why bryophytes are called amphibians of plant Kingdom

Bryophytes live in damp areas where abundant water is available. Thus, they live on land but in vicinity of water. That is why they are called amphibians of plant kingdom. They cannot live without water because:

1. They depend on an external layer of water for fertilisation
2. They do not have well developed conducting system and true roots thus need to remain at places where abundant water is available.