Aim The geographical extent and climatic tolerances of one‐ and two‐needled pinyon pines ( Pinus subsect. Cembroides ) are the focus of questions in taxonomy, palaeoclimatology and modelling of future distributions. The identification of these pines, traditionally classified by one‐ versus two‐needled fascicles, is complicated by populations with both one‐ and two‐needled fascicles on the same tree, and the description of two...