Hi Susan - most are sterile and so are grown from cuttings or graftings rather than seed. But some varieties will develop a seed pod. The article linked below explains it all in detail and if you scroll down to Fig. 14 it will show you a picture of what the seed pod (if there is one) looks like.

Good luck. ;)

Dave

Here is a link that might be useful: Gardenias

Thanks, Dave--it's an old shrub, and I've no idea of the cultivar. I'll examine it for the slight possiblity of finding a seed pod, but I'll probably hurry and take some cuttings!! ~~Susan