Small shrubby tufted perennials with acerose spiny leaves. Flowers white or pink, sessile in solitary or globose heads. Bracts spiny. Calyx cylindrical, 5-toothed, 5-15 nerved. Petals 5, limb entire or retuse. Coronal scales absent. Stamens 20. Carpophore absent. Styles 2. Ovary 4-valved. Capsule ovoid, 1-seeded, membranous below, chartaceous above, dehiscing irregularly at the base. Seeds reniform.