Answer by John Brew:
I find it very interesting that Aloe polyphlla spirals either
It is a discrete genetic trait in these plants.
PS – these plants are endemic to Lesotho but I took these photos at Paloma garden in New Zealand about ten years ago.
One other very interesting plant is the Bristlecone pine (pinis longaeva) which I have been privileged to see a few times. Here is a great specimen at Great Basin National Park, Nevada, USA.