I started paying a little attention to Clivias in the 1970's when I was growing a fairly typical orange plant (that I think my mother still grows) and fabled plants of 'Citrina' were starting to appear on peoples lists. I could have bought one from Ed Hummel, but $50 was too rich for me at the time.
Since then, yellow flowered seed strains have been developed and are becoming more widely available.
This plant, from the 'Dyna's Yellow' strain has tall flower stems and mid yellow flowers.
The ripe berries are rich yellow, instead of the usual red.