This section is from the book "Wayside And Woodland Blossoms", by Edward Step. Also available from Amazon: Wayside And Woodland Blossoms: A Guide To British Wild-Flowers.
Wandering through or round the cornfields any time from June to September we are almost sure to find this beautiful flower. It is first cousin to the Lychnis, already described, and in general structure agrees with it, only differing from it in having a leathery calyx, and in the absence of the crown of little scales which surround the mouth of the corolla-tube in Lychnis. They produce honey, but owing to the length of the tube it is only accessible to the long tongues of butterflies and moths, who are instrumental in effecting its cross-fertilization. The plant is an annual, with erect branching stem, clothed with white hairs. The leaves are long and narrow, four or five inches long. The woolly calyx is in one, strongly ribbed, with five very long leaf-like teeth, that considerably exceed the petals in length. The flowers are purple, and measure nearly two inches across.
This is the only native species; indeed, some writers consider it to be only an introduced plant - a form of Agros-tcmma gracilis that has been altered by its continuous growth in our cultivated fields.
Githago segetum. - Caryophylleae.