Experience a walk along the paths of the Arnold Arboretum through the eyes of “Painters for a Purpose,” a group of South Shore pastel artists, on Wednesday, June 29, from 6:30 – 8, leaving from the Hunnewell Building Lecture Hall. The medium of pastel is particularly suited for rendering intense colors and contrasting textures. With the Arboretum as a magnificent muse, these artists explore the landscape in all seasons, beautifully capturing changes in nature and light.  For more information, call 617-384-5209, or log on to www.arboretum.harvard.edu.  The show will run from June 11 – July 23. “Ripple” below by Nancy Poucher.