According to the Top Tropicals website, this plant was discovered in Brazil in the shade near the ocean and was found growing in sandy soils. The common name was believed to come about because it was thought that this plant would not flower until it had twelve leaves.
I am not sure if this plant's scientific name was changed because I was told the more common Neomarica longifolia was changed to Trimezia or was it the other way round. Oh, all these name changes are confusing to follow. Attached are the 3 web addresses relating to these plants: