Think you know trees? Come to the Hunnewell Building at the Arnold Arboretum on Monday, January 9, from 7 – 8:30 and learn about an amazing period when there were no trees, and then, in the blink of a geological eye, several different groups of plants evolved the ability to increase their girth and qualify for placement in an arboretum. Get a sense of what forests looked like over three hundred million years ago. Learn about the (sad) extinction of all but one of the early arborescent lineages of plants and find out which evolutionary group of trees survived to populate the Arnold Arboretum and todayâ€™s forests. The free lecture will be given by Ned Friedman, Director of the Arnold Arboretum and Arnold Professor of Organismic and Evolutionary Biology at Harvard University. Registration is required, however, so call 617-384-5277, or visit www.arboretum.harvard.edu.