|V. sororia in bloom|
|V. sororia flower - note the hairs, which ensure the distribution of pollen over the back of visiting pollinators|
|V. pubescens chasmogamous flower|
|V. sororia chasmogamous flower|
The primary disadvantage of such a reproductive strategy is of course that it restricts genetic variability enormously, which can be seriously damaging to the health of a population.
The V. sororia population I saw was quite extensive. It is rather unassuming, but quite pretty if you give it a chance:
|V. sororia population in the park|