This section is from the book "Sub-Alpine Plants Or Flowers Of The Swiss Woods And Meadows", by H. Stuart Thompson. Also available from Amazon: Sub-Alpine Plants: Or, Flowers of the Swiss Woods and Meadows.
Stems decumbent, leafy, 1-2 feet long or more, with shorter ascending or nearly erect flowering stems, ending in a leafy, forked cyme. Leaves lanceolate, hairy. Flowers nearly sessile, deep blue and handsome. Calyx-segments narrow. Nuts smooth and shining. The long, arching, leafy, barren shoots have the property of rooting at the tips, and thus the plant strides over the ground, not by creeping roots, as was formerly stated in English manuals.1
Thickets, hedge-banks, and open woods, especially on carboniferous limestone, from the plains to the hills. May to July.
Central and Southern Europe from the Atlantic to the Caucasus; rare in Britain, and only in Glamorgan, Somerset, and ajfew other counties.
This|plant is useful for covering up large areas in rock-gardens where little else will grow, but it must be kept in check.
An erect, generally branched annual about a foot high, and usually hoary with adpressed hairs. Leaves linear-lanceolate. Flowers small, white, or rarely blue in the Alps, sessile, in leafy terminal cymes. Calyx-segments nearly as long as corolla. Nuts hard, conical, and wrinkled.
Cultivated and waste places from the plains to about 5000 feet in the Western Alps and Switzerland. May to July.
Europe, except the extreme north, Central Asia, and introduced as a cornfield weed in many parts of the world. British.
Coarse, hispid plants with handsome blue or purple flowers. Corolla with a broad, open mouth to the tube, and 5 erect, equal lobes. Stamens protruding from the tube, and unequal in length. Style 2-cleft. Nuts wrinkled. Calyx deeply cut.
About 30 species inhabiting temperate and sub-tropical countries of the Old World.
Stem erect, 1-2 feet high, covered with stiff, spreading hairs springing from a tubercle. Leaves 1-nerved, the root-leaves stalked and spreading; the stem-leaves lanceolate, sessile. Flowers handsome, at first reddish purple, afterwards bright blue, rarely white. Cymes short, disposed in a long, terminal panicle. It differs chiefly from E. italicum (the only other species in Switzerland) by its simple, and not branched, inflorescence.
1 J. W. White, "The Life History of Lithospermum purpureo-cceruleum L.," reprinted, with additions, from the Journal of Botany (1884).
Europe, Western Asia, except the far north; Algeria. British.