Abstract: From the walden.org website: "To celebrate E.O. Wilson’s 80th birthday in 2009, The Walden Woods Project sponsored a second Biodiversity Day and brought together dozens of experts and amateur naturalists to reassess the biodiversity of Walden Woods. Over the 4th of July weekend [July 4, 2009], once again an extensive checklist was created..."
Also: "Lichens are a fascinating yet often neglected conspicuous feature of our rocks, soil and woody plant surfaces. We were fortunate to have experts here both years. In 1998 Elizabeth Kneiper (of Harvard’s Grey Herbaria & the NE Bot. Club) and Philip May of Harvard’s Farlow Herbarium helped out [103 species]. In 2009 Doug Greene of Reading (a major compiler of New England biodiversity), Scott LaGreca (a top lichenologist now with the Berkshire Museum) and Kay Fairweather of Carlisle found an astounding 145 species!"