Peter H. Raven, prominent botanist and conservation advocate, will speak in October as part of the Jerry Litton Lecture Series. Raven, president emeritus of the Missouri Botanical Garden, and George Engelmann Professor of Botany Emeritus at Washington University, will present “Global Sustainability: How to Achieve It.” The lecture takes place Tuesday, Oct. 3, 2017, at 5:30 p.m. in Monsanto Auditorium,…