Plants can be divided into two main groups - those that produce seeds and those that do not. Seedless plants are further divided into thallophytes (algae and fungi), bryophytes (mosses and liverworts), and pteridophytes (ferns and club mosses). Seed-producing plants include gymnosperms (conifers) and angiosperms (flowering plants). Angiosperms are divided into monocots and dicots depending on whether they have one or two seed leaves. Monocots and dicots also differ in root structure, leaf vein patterns, and flower structures.