Viola
Source
The National Gardening Bureau picked violas as their flower of the year for 2007. Violas and pansies are such relied upon stalwarts that many gardeners take them for granted and think they know everything there is to know about them. True, violas are easy to care for plants.
Source
Source
But in the gardening world, nothing stands still. Newer varieties of violas are being introduced with bolder colors and larger flowers that bloom longer. Even better, they exhibit better heat and cold tolerance than the remarkably hardy varieties we're familiar with.
Primulas
primrose pin and trum flowers
Source
Primroses are actually hermaphrodites - but they have 'pin' and 'thrum' flowers - one with short male parts and long female parts (pin), and the opposite for thrum. This is under genetic control.
primula eliator, pin
Source
I don't know if anyone has experimentally been able to overcome the genetic basis, but most likely if they did it would be impossible to duplicate inexpensively outside of a highly controlled laboratory setting.
primula eliator, trum
Source
Primroses are actually hermaphrodites - but they have 'pin' and 'thrum' flowers - one with short male parts and long female parts (pin), and the opposite for thrum. This is under genetic control.
primula eliator, pin
Source
I don't know if anyone has experimentally been able to overcome the genetic basis, but most likely if they did it would be impossible to duplicate inexpensively outside of a highly controlled laboratory setting.