Flax have been domesticated just once from the wild species "Linum bienne", called pale flax. Several other species in the genus "Linum" are similar in appearance to "L. usitatissimum", cultivated flax, including some that have similar blue flowers, and others with white, yellow, or red flowers. Some of these are perennial plants, unlike "L. usitatissimum", which is an annual plant. Cultivated flax plants grow to tall, with slender stems. The leaves are glaucous green, slender lanceolate, 20–40 mm long, and 3 mm broad. The flowers are pure pale blue, 15–25 mm in diameter, with five petals. The fruit is a round,
Ditherington Flax Mill fibres, by using a fireproof combination of cast iron columns and cast iron beams, a system which later developed into the modern steel frame which made skyscrapers possible. Along with the main Flax Mill, a number of other buildings in the group are listed for their architectural and historic value: the apprentice house (Grade II*); the dye house (Grade II*); the flax dressing building or Cross Mill (Grade I); the flax warehouse (Grade I); the stables (Grade II); and the workshops and offices (Grade II). The mill and buildings are on the Heritage at Risk Register. Ditherington Flax Mill Ditherington