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.
The plant is normally quite 2 ft. in height. It flowers in May and June. It is annual, propagated by seeds.
The honey, which is scanty, is protected by hairs and secreted at the base of the lube near the smooth ovary, the tube being 4 -5 mm. long, 1 mm. wide in the lowest part. The stamens are inserted on the corolla below the middle. The anthers open inwards longitudinally, and pollen is set free before the flower opens, though in some the stigma is ripe first. The short style (2 mm.) ends in two small rounded lobes, with ring-like lobes beneath, which are covered with warts. They are level with the anthers, and take up the space to the base of the flowers. The stamens curve outwards at the top and guide the insect's proboscis to the flower centre, so that it passes between the anthers and the stigma. It in a young flower an insect thrusts its proboscis which bears pollen from another flower into it, it cross-pollinates it, and fresh pollen also adheres to the proboscis. As pollen is withdrawn it is finally self-pollinated, a mode which is necessary on account of the few insect visits and small flowers, growing amongst corn. It is visited by the butterflies, Large White (Pieris brassicae), Small White (P. rapae). and by bees and Syrphidae.
The smooth nutlets when ripe fall around the parent plant, or are dispersed directly by birds, game, etc.
Gromwell is a sand plant, growing on rock soils which afford a sand soil.
Photo. A. R. Hopwoo - Corn Gromwelx (Lithospermum arvense, L.)
A fungus, Peronospora myosotidis, attacks the leaves. Two moths, Anescychia pusiella and A. decemguttella, and a fly, Chromatomyia albipes, are the chief insect pests.
Lithospermum, Dioscorides, is from the Greek lithos, stone, and sperma, seed, alluding to the hard stone-like seeds; and arvense indicates its occurrence on arable land.
Gromwell is possibly from granum milii. It is called Bastard Alkanet, Lichwale, Painting Root, Pearl-plant. Salfern. Corn Gromwell is called Painting Root because girls in the north were said to paint their faces with the juice of the root on festival days.
The stony seeds were, by the "Doctrine of Signatures", used in cases of "Stone", hence lich wale, lythe wale, and stone switch. A red dye has been prepared from it for paper and linen. In Sweden the women stain their faces with it as rouge. The dye is readily applied to oily substances, hence the name Bastard Alkanet.
Essential Specific Characters: 218. Lithospermum arvense, L. - Stem erect, branched, leaves linear-lanceolate, hispid, flowers creamy-white, nutlets tuberculate.