Following on from a discussion started under a photo posted by Pauline M (id 376193 15 Oct 21):

A couple of days ago I saw potted Black Boys in a local nursery in Sydney. Only one flower was out at the time, a large, somewhat loose, red bloom with black shadings. Knowing that there have been some impostors offered as 'Black Boy' over time I was hesitant to buy one before I looked closely at the file photos here again. I admit I became a bit confused since there seems to be quite a difference in the appearance of the flowers. So I went back today planning to buy one and try it out and observe it over time.
The same plant with the one large flower was still there but another bud on that same plant, that hadn't opened the other day when I saw it, was now fully open. What amazed me though was how small it was in comparison to the other older flower! I estimate the first flower was about 4 1/2"/12cm, but this newly opened flower was at best only about 2"/5cm. It was also quite different in form too being flatter and more rounded. Maybe it will expand more but I doubt it will get to the size of the first flower.
I then reckoned that if the flower appearance can vary so much on the same small specimen at the one time it must vary considerably more on larger plants at different times of the year, and in different growing conditions, hence a lot of variability in the photos here. Therefore, being a bit more reassured, I bought one to try out.