A small family, widely distributed in temperate and tropical regions. Ours are smooth herbs, with loosely clustered, complete flowers, having five sepals; five petals, alternating with the sepals; five stamens, alternating with the petals, with swinging anthers and filaments united at the base; ovary superior; fruit a capsule, containing eight or ten, oily seeds.

There are many kinds of Flax, sometimes shrubby at base; with tough fibers in the bark; leaves without stipules, sometimes with glands at base in place of real stipules; flowers mostly blue or yellow. There are numerous, small-flowered, annual kinds, difficult to distinguish and usually somewhat local. L. usitatissimum, an annual, with deep blue flowers, is the variety which, from time immemorial, has furnished the world with linen from its fiber and oil from its seeds. Linum is the ancient Latin name.