Helianthemum nummularium, commonly known as common rock-rose, is a low-growing perennial wildflower native to Europe. It is distinguished by its bright yellow, cup-shaped flowers that open in sunlight, and its small, rounded, evergreen leaves that form dense mats. Unlike many wildflowers, it thrives on dry, calcareous soils, often in grasslands, rocky slopes, and sunny meadows. Its flowers provide an important nectar source for bees and butterflies during the summer months, while its mat-forming growth helps prevent soil erosion, making Helianthemum nummularium a key species in supporting pollinators and maintaining the structure of dry grassland ecosystems.