How do you think botany was taught in the 1800s? TPP almost said "in the last century", but then realized what that now means, and he's an expert on the last 50 years of that century having lived it. Marshall Sundberg is one of my best colleagues, and we've collaborated at times on several educational projects. Now what TPP knows that you don't know is that his wife is a professional historian, and clearly she has rubbed off on him in more ways than just his improved grooming and table manners. Old botany textbooks provide a lot of information about what and how botany was being taught. Here's a link to Art Plantae where they have a nice article about his project.