Our mind completes a circle. This is why it works to take a picture of part of something round. We fill in the blanks and complete what is missing quite easily. This works for close-ups of people's faces, sunsets, pumpkins...you name it. If it is round, or close to round, you can get away with not including the whole of the round.
I chose to present this image in black and white, void of colour, to accentuate the textures and shape of the sunflower.
Using my 60 mm macro lens, I shot at a speed of 1/160 with an aperture of f/2.8.