13. Xenostegia D. F. Austin & Staples, Brittonia. 32: 533. 1980.
地旋花属 de xuan hua shu
Merremia sect. Halliera O'Donnell.
Herbs perennial, prostrate or tips ± twining. Leaves petiolate, linear, oblong-linear, lanceolate-elliptic, or oblanceolate to spatulate, base ± hastate; basal lobes ± clasping stem, dentate or entire, apex acute to emarginate, mucronate, or tridentate. Inflorescences axillary, cymose, 1(-3)-flowered. Sepals oblong or oblong-ovate, ± equal to unequal, acute or obtuse; inner 3 narrower, apically tapering into slender points, all enlarged in fruit. Corolla pale yellowish or whitish, often with a purplish center, broadly funnelform or campanulate. Anthers not twisted at dehiscence; pollen globose, pantoporate, not spiny. Pistil included; ovary 2-loculed, 4-ovuled. Style 1, filiform; stigmas 2-globular. Capsule 4-valved, glabrous or pubescent apically. Seeds 1-4, brownish to black, ovoid-trigonous.
Two species: tropical regions of Asia, Africa, and Australia; one species in China.