Plants of the polemoniaceae (phlox) family are mostly found in the US, particularly in the west, inhabiting all environments from the coast and the low deserts to high mountainsides. The US has 308 species in 19 genera. Plants are usually small herbs bearing many leaves, which may be simple or pinnately divided. Flowers are formed of five sepals, fused at the base extending to narrow tips, and a tubular corolla that opens to five spreading lobes, generally much wider then the tube. At the center are three stamens and a three-pronged style, which may be included or exserted. Most species have radially symmetric flowers but a few have flowers in which two adjacent lobes are closer to themselves than the other three.