What can the presence (or absence) of greenery teach about the layered history of a place? This New England Wild Flower Society walking tour of Cambridge leads participants in an analysis of the changing landscape, guided by evidence from significant trees in the neighborhood. The discussion addresses local inhabitants’ relationship to native plants over generations. Wear walking shoes and dress for the weather. The tour is led by Courtney Allen, garden historian and Director of Public Programs at NEWFS. Place to meet will be sent to registrants. $24 for NEWFS members, $28 nonmembers. Register online at www.newenglandwild.org.