The pilot was receiving instruction from a flight instructor in the tailwheel-equipped airplane to become a glider tow pilot. The pilot landed the airplane on the grass next to the paved runway, an area that included a paved taxiway that crossed over it. Upon reaching the taxiway the airplane bounced and swerved to the right. The pilot corrected with rudder application and braking, but the airplane continued its right turn and ground looped. During the ground loop the left main landing gear collapsed and the left wing impacted the ground, substantially damaging it. The flight instructor reported that there were no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation. The flight instructor also reported that he could have been faster in taking control of the airplane after it initially began to turn, but had relaxed because they were in the roll out phase of the landing, and because the pilot had previously landed the airplane without issue.