A vegetation formation characterized by woody plants of low stature (3–9 ft or 1–3 m tall), impenetrable because of tough, rigid, interlacing branches, with small, simple, waxy, evergreen, thick leaves. The term refers to evergreen oak, Spanish chapparo, and therefore is uniquely southwestern North American. This type of vegetation has its center in California and occurs continuously over wide areas of mountainous to sloping topography. The Old World Mediterranean equivalent is called maquis or macchie, with nomenclatural and ecological variants in the countries ranging from Spain to the Balkans. Physiognomically similar vegetation occurs also in South Africa, Chile, and southwestern Australia in areas of Mediterranean climates, that is, with very warm, dry summers and maximum precipitation during the cool season.