Well, a Begonia isn't very exotic, so it always comes as a surprise that so many people don't notice what they are looking at. Yes, flowers. But Begonia is a monoecious plant. Mono = one, ecious = house, so this means the plants usually, but not always, have both male and female (and yes, this is technically wrong) on the same plant (one house). What tricks people is what tricks pollinators too. The only obvious reward is pollen, and male flowers (center) have a cluster of yellow stamens that are pretty obvious against the light background of the perianth. But only one of these flowers has stamens. The others have a conspicuous yellow stigma presenting a very similar image. If pollen is the only reward, then the non-rewarding female flowers cruelly deceive the pollinators by mimicking the rewarding male flowers. This is called food-deception automimicry. The flowers are different in another very obvious way that many people also fail to notice; the females flowers have a prominent winged ovary below the perianth, and a similar structure is completely lacking on the male flowers. The ovary is sort of petalloid, and that may be the reason people don't notice. Since the summer is here, apply this lesson to your cucumbers and squashes.