Cistus clusii -my own attribution

From the Southwestern Iberian Peninsula. Small, 1cm long, narrow leaves on a petite shrub, bright white flowers 2cm diameter with a yellow blotch. Long flowering over summer. Hardy and drought tolerant. It is small and tidy, not lax (this and C. libanotis are often confused) It has a habit not unlike a wild species of Helianthemum. 

Neojavi2001, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons