idk if you've been to the relevant parts of South Africa (roggevelt escarpment) but thoughts on genus Daubenya? I got some alba and aurea seeds from the local chaotic neutral mail order place that i'll try growing as houseplants.
I was around there (near Tankwa Karoo) in December but the parks were rained out so I didn't get to check out the wildlife that much, plant or animal, although I spent a while up in the mountain passes.
No experience growing Daubenya, especially not from seed, that sounds tricky. They're quite rare, too, so I don't think I've seen them in the wild the handful of times I've been near the Karoo. Good luck with getting them to grow, though!