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.
As yet no traces of this plant have been found in seed-bearing deposits. It is found throughout the Warm Temperate region in Europe and W. Asia. It has been introduced into the United States. Though common in most parts of Great Britain, Hedge Mustard does not occur in Brecon, Radnor, Montgomery, Merioneth, Peebles, Selkirk, Mull, and the Shetlands. It is found in Ireland and the Channel Islands.
The Hedge Mustard, as the name suggests, is found by the sides of our roads and hedges, and may be said to be most common near villages and houses, and may possibly owe its distribution largely to former herbal usage. It is also a regular member of the flora of waste ground, where it ousts many more tender plants, being a vigorous plant which occupies much space.
Like some other plants, Hedge Mustard has two different habits, before and after flowering. Before flowering it has a main stem, hairy, and often purple, as in Winter Cress, with numerous leaves, with segments divided nearly to the midrib and with the lobes turned back, prostrate on the ground, and few above. In this form it is similar to many plants with cyclic foliar arrangement and erect stem. When the flowers have opened from a series of dividing branches, and have commenced to produce fruit, the aspect is rather like that of a candelabra, and by this time the basal rosette of leaves has usually disappeared. The plant is frequently covered with dust, more so than most wayside plants.
It may be distinguished by its small yellow terminal racemes of flowers borne on leafless branches. The pods are closely united to the stem throughout their length, long, acute above, with sharp style, and borne on short flower-stalks, being usually downy. The leaves have a terminal pointed lobe, and lateral ones with the points turned back. The Hedge Mustard is often 2 ft. high. It flowers from May to July. It is annual, and reproduced by seed.
The flowers are similar to those of Alliaria. On each side of the 2 shorter stamens are honey-glands, and each of the 4 honey drops lies between the stamens and the pistil. The anthers and stigma ripen together, and the former face the latter.
The longer anthers are at first taller than the stigma, and project when the flower opens and bend inwards; the shorter ones, at first within the flower, being ultimately on the same level, but not quite so long as the stigma, curve outwards slightly. They all six grow, and the longer ones exceed the stigma. Cross-pollination is arranged for, but may not occur. In the absence of insects pollen from the four long stamens falls on the stigma. The flowers are inconspicuous and visits are infrequent, but honey is sought by Pieris napi, P. rapce, which thrust the proboscis between the stigma and anthers. Pollen is sought by Andrena dorsata. The insects visiting it are Hymenoptera (Apidae, Andrena dorsata), Lepidoptera, as above.
Hedge Mustard is dispersed by its own agency. The pods open and allow the seeds to fall out around the plant, or disperse them to some distance.
Photo. W. E. Mayes - Hedge Mustard (sisymbrium Officinale, Scop.)
It is a sand-loving- plant, and requires a dry sand soil or sandy loam, derived from older sandy rocks, grits, and sandstones.
It is galled by Cecidomyia sisymbrii. A beetle, Ceuthorhynchus assimilis, visits it, also the beetles Phyllotreta nemorum, P. ochripes, Poophagus nasturtii, P. sisymbrii.
Theophrastus gave the name Sisymbrium, which was the Greek name of a water-mint, and officinale means medicinal.
The plant is called Bank Cress, Hedge Mustard, Hedgeweed, Lucifer Matches, Crambling Rocket, Sauce Alone.
Hedge Mustard was eaten as a relish with salt fish, hence the last name, and was used in sauce. It was held to be diuretic, expectorant, and was regarded as a remedy for asthma, hoarseness, and chronic coughs. This plant has a somewhat saline taste. The seeds are pungent, but not so strong as mustard.
Essential Specific Characters: 31. Sisymbrium officinale, Scop. - Stem erect, branched, divaricate, leaves at base runcinate, points recurved, terminal lobe hastate, upper linear or absent, flowers small, yellow, pods appressed on short pedicels, downy, subulate.