This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Tall herbaceous or suffruticose plants, usually clothed with rough hairs having a thickened base. Leaves entire. Flowers blue, violet, red or white, in spiked or racemose panicles. Calyx 5-lobed. Corolla cylindrical or funnel-shaped, with a dilated naked throat and an unequally 5-lobed limb. Stamens exserted; anthers free. Nuts 4, rough, inserted on the flat receptacle by a flat base. There are about fifty species, chiefly from the Mediterranean countries and South Africa. The generic name is from a viper, from the resemblance, it is said, of the seeds or nuts of some species to a viper's head. The Viper's Bugloss, E. vulgare, is a handsome indigenous species with reddish purple, ultimately blue, or rarely white flowers. It grows from 1 to 3 feet high, and is of annual or biennial duration.
E. violaceum is an allied species with long simple spikes of remarkably bright violet-blue flowers. E. Creticum is a dwarfer annual plant with red flowers; and E. pomponium a tall biennial with flesh-coloured flowers.
Borrago officinalis, Borage, occasionally seen in gardens and waste places, is a distinct plant with broad sinuate leaves and large blue flowers with conspicuous black anthers. The flowers are borne in a loose cyme, and remarkable for the rotate deeplylobed corolla having broad notched scales at the mouth of the tube.