This short video was possible because our neighbours (Carolyn and Jim) loaned me the barrel cactus just as it was starting to bloom. The stalks elongated for about three days, then at 7:00PM on the appointed day, the bloom began to open. Fully open by 10 PM, the bloom withered and died the following night.
The timelapse was taken using a Canon XL H1s using a nanoflash. The closeups are with the same camera but substituting a Nikon lens.