Plants perennial. Stems prostrate, much branched, forming loose mats, elongate, densely glandular-pubescent, viscid. Leaves: petiole 2-4.5 cm; blade elliptic-oblong to rhombic-ovate, 1-2.5 × 0.6-1.5 cm, margins entire to repand and ± undulate, surfaces glandular-puberulent. Inflorescences: peduncle longer than subtending petiole; bracts lanceolate to elliptic, 3-5 × 1-3 mm, papery, puberulent to glandular-pubescent; flowers 15-35. Perianth: tube greenish, 7-12 mm, limb greenish white, 4-6 mm diam. Fruits biturbinate, tapered at both ends , ± rhombic or fusiform in profile, 4-6 × 2.5-4.5 mm, indurate; wings reduced, appearing as 5 prominent lobes near middle of fruit; peripheral fruits not or only slightly distorted. Flowering summer-fall. Sandy soils, lake shores; of conservation concern; 2300-2500 m; Wyo. Abroniaammophila is found on the beaches of Yellowstone Lake, Yellowstone National Park.