That whole middle area looks like royal icing. Maybe you could buy stamens and pipe royal icing in those colors onto them.
The yellow part looks like a piece of gumpaste on a wire, and then royal icing piped on top.
Edited to say: I just realized that the picture is of a real lotus flower. Nevertheless, I think you can recreate the middle using royal icing.
i was thinking gumpaste for the big middle center too, but i'm not sure how to get the stamens to stand up like that (like, hair maybe?). could royal icing stay up like that? maybe i can just use wires and wrap them with a thin layer of gumpaste. i'll try out different techniques. thanks for the tips.
Using Royal to make the stamens would be a PITA. You can purchase non-edible stamin at most specialty cake supply stores. You can also order them online. http://www.sugarcraft.com/catalog/gumpaste/stamens.htm is one place. I have a local specialty supply store, so I just go there.
I'm in the middle of making a lotus as well, and for the center I made a ball of gumpaste to stick the stamen into, then attached the bell thingy that I made from gumpaste also. Then I stuck the stamen in behind the bell, and that is the best way I have figured out how to make one.