Painting a mushroom

[gypsylou.livejournal.com]

Hello, I was wondering if anyone has any good ideas on how to paint a mushroom? My uncle has been making me photography props. He made a mushroom out of foam (inside) and plaster (outside). It is about a foot and a half high. What should I use to paint on it and how can I get the spots on without it looking like it is painted on? And what color would a mushroom be for taking pictures? Any suggestions would be very appreciated. Thanks!