This plant is not Aloe zebrina, which has different inflorescences (cylindrical and relatively tall, laxly flowered). I realize this plant was in a botanical garden but they apparently have it misidentified. Unfortunately it is very hard (especially for me) to distinguish different species of spotted aloe, so I would not be able to provide a more suitable name as an alternative.
I would like to move this image to the generic listing for Aloe, unless you have more specific information. Please let me know what you think.