While on approach for a short field landing, the flight instructor reported that the pilot undergoing instruction added power to arrest an excessive rate of descent at his instruction but removed it when the flight descended below 100 ft. The airplane began to descend rapidly and during the flare touched down first on the nose landing gear. The flight instructor took control of the airplane and added power to abort the landing, but he reported the nose dropped and the airplane began to, “...porpoise down the runway while the stall warning was sounding.” He attempted to keep the nose level but the airplane bounced about 5 or 6 times before coming to rest at the edge of the runway near the midpoint. The pilot reported that the approach was, “...a bit steep and fast due to gusty conditions.” He also reported the canopy became unlatched during the porpoising, and he held it down to prevent getting hit by debris kicked up by the propeller. A review of pictures of the airplane revealed it came to rest with the right main landing gear partially collapsed. The top center portion of the fuselage was substantially damaged during the accident. The pilots reported that there were no mechanical malfunctions or failures of the airplane that would have precluded normal operation.