Plants that do not reproduce by seeds are called non-seed plants. There are two main categories of non-seed plants:

1. Ferns and their relatives (Pteridophytes):

* Ferns

* Horsetails

* Whisk ferns

* Lycopods (club mosses and spike mosses)

These plants reproduce using spores, which are tiny, single-celled structures that can develop into new plants.

2. Bryophytes:

* Mosses

* Liverworts

* Hornworts

These plants are even simpler than ferns and lack a vascular system. They also reproduce using spores.

Note: There are also a few other plants that don't reproduce by seeds, like some algae and fungi, but they are not typically considered part of the plant kingdom.