30. Petrorhagia (Seringe) Link, Handbuch. 2: 235. 1831.
膜萼花属 mo e hua shu
Lu Dequan; Richard K. Rabeler
Gypsophila Linnaeus sect. Petrorhagia Seringe in de Candolle, Prodr. 1: 354. 1824.
Herbs annual (or perennial). Stems erect or ascending. Leaves linear or linear-subulate; stipules absent. Inflorescence a cymose panicle, (rarely capitate); bracts subtending calyx in 1--4 pairs or rarely absent. Flowers small. Calyx campanulate, 5(or 15)-veined, scarious between veins, 5-toothed. Petals 5, white (or reddish), (with or) without claw; limb entire (or emarginate). Stamens 10. Ovary 1-loculed; ovules numerous; styles 2. Capsule oblong or ovoid, dehiscing by 4 teeth or valves. Seeds numerous, dorsiventrally compressed, ridged-winged, tuberculate or smooth; embryo straight.
About 30 species: Mediterranean region to C Asia; one species in China.
Petrorhagia saxifraga (Linnaeus) Link var. saxifraga is cultivated in China. It is a perennial, with four bracts immediately subtending the calyx, and reddish or white petals.