Kingdom Plantae includes all plants: mosses, ferns, conifers, flowering plantas, and more. There is more than 250,00 species around the world. The most important characteristic about plants, it's their green color, which is the result of the pigment chlorophyll. Without the plants the earth would be really boring, because it would be only deserts, a deep ocean and arctic wastelands. No trees, grass, nothing. Through photosynthesis they make their own food, so they are autotrophs.