Here are some results from the cross-pollination between three B. guehoi plants.
Plant A and B - overlapping petals
Plant C - non-overlapping/less overlapping petals
Plant A's pulvini
Plant C's pulvini
Check out the fruit formed on Plant C where the upper right arrow is. The arrow on the lower left is shows the region represented by the photo above.
1. All of Plant A's pedicels hang down and pulvini are very much enlarged. Pollen was from Plant C.
2. Plant B has flowers similar to Plant A and its pedicels hang down, similarly with pulvini enlarged. Pollen was from Plant C.
3. Plant C's pedicels stay mostly upright though some are lowered (to a lesser extent than Plant A and Plant B). Pulvini remain small. Pollen was from Plant A.
4. Fruits from all three plants look viable (but I'll update once they split if they do contain seeds).
p.s. I am assuming that there is no natural pollinator over the past few weeks