I decided to draw a purple iris for the contest of 
First I drew the contours of the drawing with a pencil.
With emerald green and blue paints and translucent layers drew the background. At this stage the first layer of the paints must impregn the cardboard.
With grassy-green paint, mixed a bit with yellow, painted over the leaves in the foreground of the picture.
I painted the petals of the central iris with a violet paint. At this stage, it is also important to soak cardboard, and then I could pay attention to detailing the flower. Painted with the same violet paint unopened buds.
I added to the purple paint a little black and with a thin brush paint drew the main shadows on the petals of the central iris.
I mixed violet, red and white paint, getting a delicate pinkish-violet color. With the resulting shade, I painted over the petals of the central iris. With longitudinal thin lines I tried to convey the shape and bends of the petals.
With dark-violet paint I drew shadows on the buds of iris, showing their shape. Just as on the central flower, I drew pinkish-violet longitudinal lines on the buds. Leaves in the foreground I painted with a mixture of green, yellow colors and light ocher.
At the final stage, I strengthened the detailing of the picture, shadows and intensified the light flare. It is much easier to do this, because the cardboard has been soaked with the previous layers of paint and now it's better to keep the color, the colors turn out bright and juicy. Light glare I drew in the most illuminated places and edges of flowers and leaves with light-white paint and white paint. The drawing is ready.
Gif of the process.
I apologize if you find mistakes in my text. Unfortunately, my English is not perfect.
