This section is from the book "British Wild Flowers - In Their Natural Haunts Vol2-4", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
Seeds of the Lamb's Lettuce have been found in Interglacial beds at West Wittering. The plant is found throughout the Temperate Northern Zone in Europe, N. Africa, and Western Asia. In Great Britain it is absent in Hunts, S. Lines, Kirkcudbright, Stirling, Mid Perth, N. Perth, Elgin, Westerness, Cantire, S. Ebudes, N. Ebudes, W. Ross. Watson regards it as doubtfully native.
Corn Salad or Lamb's Lettuce is a typical cornfield weed, being always found on cultivated land unless it be waste ground, where it is sometimes to be seen. It orows with Heart's Ease, Corn Marigold, Venus's Looking Glass, Scarlet Pimpernel, Field Bugloss, Hemp Nettle, and many another sand-loving species.
Lamb's Lettuce is a short, erect plant, with an angular, furrowed, downy, slender stem, divided into two repeatedly, with numerous radical leaves, smooth-veined, spoon-shaped, the upper ones stalked, opposite, distant, fringed with hairs, and notched.
Photo. H. Irving
Lamb's Lettuce (Valerianella Olitoria, Poll.,)
The flowers are blue and numerous, borne in close terminal cymes, surrounded by long narrowly elliptic bracts. The fruit is naked, flattened, spuriously 2-3 celled, and contains one seed with a corky mass on one side; the barren cells touch, and are not furrowed, being separated from the fertile seed by grooves on each side. This reduction of the fertility of the ovules may conduce to the lightness of the seed, and enable it thereby to be more widely dispersed by the wind.
The plant is from 6 in. to 1 ft. high. It flowers in April and May. It is annual and propagated by seeds.
The flowers are small and lilac, and the plant grows amongst corn, and is therefore less likely to be insect-visited than the Marsh Valerian, though concealed honey is found. There are only 3 stamens and 3 stigmas, which are simple. The anthers and stigma may ripen together, or the latter first. The visitors are Coleoptera, Diptera, Hemiptera, Apidae, Lepidoptera.
The fruit, besides being flattened, is spuriously 2-celled, and being small is easily dispersed by the wind.
The moth Caradrina cubicularis, a Hymenopterous insect Trioza centranthi, and a fly Chromatomyia albiceps feed upon it.
Valerianella, Columna, is a diminutive of Valeriana, and the second Latin name refers to its use as a salad.
The English names are few, such as Cornel-sallet, Corn Salad, Lamb's Lettuce, Milk Grass, Potherb.
Gerard says: "In English the white potherbe, so called for that there is a blacke potherbe, which is called Alisander". The name Milk Grass may be said to be due to the following: "In June at a distance the fields look as if all covered with spilt milk, which is from a flower for that reason called Milk Grass (Lamb Lettuce), for it has now lain for six or seven years lee".
Lamb's Lettuce is used as a salad plant, and has been cultivated for a long time.
Essential Specific Characters: 146. Valerianella olitoria, Poll. - Stem repeatedly 2-forked, spreading, slender, leaves ovate, toothed at base, flowers blue, in terminal cymes, capsule compressed, with ciliate bracts.