Plants can be divided into three main groups based on their reproduction methods: 1) Non-seed producing plants like algae, fungi, mosses and ferns reproduce using spores and lack true roots, stems and leaves. 2) Gymnosperms are seed-producing but flowerless plants like conifers that bear cones and have exposed seeds. 3) Angiosperms are flowering plants that have seeds enclosed in fruits; they are divided into monocots and dicots. Monocots have single cotyledons while dicots have two.