This section is from the book "British Wild Flowers - In Their Natural Haunts Vol2-4", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
One usually associates a cornfield with masses of scarlet poppies or sulphur-yellow Charlock. In favoured localities a touch of puce or magenta is lent by the Corn Cockle, but this plant seldom grows en masse, and the same may be said of the Cornflower, which like the last is dying out of the cornfield. On rich red soils the Corn Marigold may here and there contribute a golden glow to the cornfield.
These, however, are the jewels of the cornfield, as the buttercups and lady's smocks and red clovers are in the meadows. As a whole we may indeed regard the cornfields as devoid of brilliantly-coloured flowers. Many are white, or nearly so, such as Candytuft, Heart's Ease, White Campion, Spurrey, Shepherd's Needle, Fool's Parsley, Lamb's Lettuce, Blue Sherardia (pale lilac), Corn Gromwell, Hemp Nettle (white or pink), and a number apetalous.
This may be connected with another factor which is characteristic of the cornfield, namely, the inaccessibility of the cornfield plants to the insects that visit, as a rule, the brilliantly-coloured flowers.