Whenever we are painting flowers I point out the difference between monocots and dicots, a handy thing I learned in first year biology. The number of petals in spring bulb flowers is usually a multiple of three and the leaves have stripey, parallel veining. These two features are typical of monocotolydenous (one seed leaf) plants. Dicotyledonous (two seed leaf) plants have leaves with reticulated veining and their flowers usually have petals in multiples of four or five (and it is all well described at this page.) "Usually", and up until this lesson, unvaryingly, but these flowers hadn't heard of the phenomenon or read the text books and instead flaunted their pretty seven-petalled heads at me. "Paint what you see" is a good rule too and the one to follow when theories don't seem to fit.
Last year's pansies were much more obedient!The important thing is to keep painting, whether following familiar trails or breaking a new path.