A cropped, scaled down image of this orchid (from the random images on the forumhome of your site) just to the right of the Orchids Forum text in the logo might work.
http://xenforo.com/community/resources/recent-random-attachments-on-forum-homepage.1415/Fantastic idea for a forum and it looks professional. I'm curious, how do you get the random attachments to be on the front page?
Ah, thank you very much! It looks like I could use it for a photo forum I might start.