phlox, common name for plants of the genus Phlox and for members of the Polemoniaceae, a family of herbs (and some shrubs and vines) found chiefly in the W United States. The family includes many popular wild and garden flowers, especially the genera Phlox, Polemonium (called Jacob's ladder), and Gilia, a plant common in desert and mountain areas. Although most phloxes are perennial, the common garden phloxes are annual hybrids of the Texas species Phlox drummondii. The moss pink ( Phlox subulata ) is a creeping evergreen plant native to the E United States and often cultivated in rock gardens. A few species of phlox and polemonium are found in E Asia. The phlox family is classified in the division Magnoliophyta, class Magnoliopsida, order Polemoniales.