Thank you to Makita who left comments here and the rest of you who left comments in Facebook, for your advice on how to handle this unexpected situation. Your ideas helped me with my response. I sent an email reply again describing the nature of the doctoral program that I am in and that the degree is not a Ph.D. I said that the training received in the program includes botany but we learn much more. I told them what that more was. I said that the program is application based rather than research based, but that I have research experience from my M.S. studies and from working as a molecular biologist. I also mentioned what topic I would choose to give a seminar on if I gave one there.
The reply that I got back was that they would be happy for me to give a seminar on that topic. So I am going! I'm already booked for the flight. I will spend the weekend meeting and visiting with all of the faculty and then give my seminar on Monday, March 1.
I'm both excited and nervous.