It is a release spring. The spring goes inside the clutch, in between the pressure plate and clutch hub. It assists in pushing the pressure plate out and away from the clutch to dis-engage it when you squeeze in the clutch hand lever. It is not the main pressure spring that clamps down everything to lock up the clutch when you release the hand lever.
The flower nut is the adjustable nut that fits onto the clutch center stud. It is adjustable so you can tune the clutch for proper operation.
Here's Norm's tutorial on clutches: http://motorbicycling.com/showthread.php?t=222
Here's a tutorial I made on adjusting them with excellent additions by KCvale.