David Fairchild (1869-1954), the founder of the famous Fairchild Tropical Botanic Garden in Florida attended a lecture by Wallace in Kansas when Fairchild was at college there. Afterwards Wallace was a guest in Fairchild's father's home (his father was the president of Kansas State Agricultural College in Manhattan, Kansas). Wallace inspired Fairchild who later said “I like to imagine that it was this meeting with the great naturalist which started my longing to see, when I grew up, those islands of the Great East - the Malay Archipelago.” David went on to become "One of the most influential horticulturalists and plant collectors in the country, [he] was the first Chief of the Office of Foreign Seed and Plant Introduction Section and worked for the USDA for 37 years."
According to Charles Smith & Megan Derr's 2013 book Alfred Russel Wallace's 1886–1887 Travel Diary: the North American Lecture Tour, Wallace gave a lecture entitled "Darwinism" in Manhattan, Kansas on Monday 9th May 1887 (which was attended by nearly 400 people) and in the evening he had dinner with David Fairchild's father George (1838-1901). This must have been the occasion that David (then aged 18) met Wallace.
The Fairchild Tropical Botanic Garden is featured in the following documentary entitled The Fruit Hunters on YouTube: http://youtu.be/3Qnpjt5KzYQ