How big was the flower? Bulbine bulbosa and Bulbine glauca have petals 9 mm long and up, Bulbine semibarbata petals are 4-7 mm long. The two bigger ones are differentiated on the anthers - bulbosa has stamens attached at one end that point up; glauca stamens that are attached about the middle so they look as if they are curling round the hairy tuft. I cannot see the anthers at all in your photo.