The wonders of colour vision

How different the world would look if we apes had not evolved colour vision or if, for example, our retinas had only cones sensitive to blue wavelengths?

In that case the delightful blue flower plant known as the green alkanet Pentaglottis sempervirens might look to our eyes something like this. 

You may well wonder why a plant with blue flowers is known as the green alkanet. It is because it is an evergreen, the clue being in the specific epithet, sempervirens, always green.