The four main plant groups include Bryophyta and allies, Pteridophyta and allies, Coniferophyta and allies and Magnoliophyta. Plants from these groups all fall into one of three groups: nonvascular plants, vascular plants with spores and vascular plants with seeds.
Plants are broken into divisions based on their characteristics. The divisions sort according to whether they can circulate fluids through their bodies or whether it is necessary for them to absorb fluids from their surroundings. Another characteristic used to determine their division is how the plant reproduces, from seed or spore. Finally, a plant's size or stature helps determine its division.