CISTACEAE: Rockrose Family
KEY TO SPECIES OF HELIANTHEMUM
1. Underside of leaf blades on main twigs light green and with minute clustered hairs, the hairs up to ca 0.18 mm; outer sepals of flowers that open 0.7-1.2 mm across, narrowly spatulate; cliestogamous flowers and their fruits in compact clusters of a few to many .................................................. H. corymbosum
1. Underside of leaf blades on main twigs grayish with abundant clustered hairs, the hairs up to 0.3 mm; outer sepals of flowers that open 0.3-0.5 mm across, linear to narrowly awl-shaped; cliestogamous flowers and their fruits well separated or in clusters of a few ........................................................ H. arenicola