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.
There are no deposits from which this is known in a fossil state in the British Isles. It is a plant which is found in the Temperate Zone in Europe, North Africa, Temperate West Asia, as far as the Himalayas. In Great Britain it is found everywhere except in Cardigan, Flint, S. Lincs, Stirling, Mid Perth, Main Argyle, Cantire, S. Ebudes, Mid and N. Ebudes, Sutherland, Caithness, and the Northern Isles. From the Grampians it ranges southwards, up to a height of 1000 ft. in England, but it is less common in Scotland and Ireland.
Garlic Mustard grows with Hedge Mustard along the wayside and beneath the hedge, or it may line the ditch which flanks the highway. Once used as a garnishing it may to some extent owe its frequency around a village, or its occurrence on highways, to this cause. A rather moist habitat suits it best, though it will grow on a high bank where there is shade enough to maintain a fair supply of moisture continuously. It manages to win its way to the front in spring to the exclusion of all else, but may be seen with the Greater Stitchwort, Red Campion, Lords-and-Ladies, etc.
Jack-by-the-hedge is a tall, handsome plant, with an erect habit, and numerous heart-shaped, toothed leaves alternately arranged, the leaves being coarsely veined, and moved by heliotropic tendency to turn towards the sun, on each aspect towards the greatest source of light. The plant smells strongly of garlic, especially when the leaves are bruised, quite as much as Ramsons.
All the leaves are borne on long foot-stalks, and the broad, deep teeth give their leaves a notched appearance.
The flowers are white and small, the petals are stalked and inversely egg-shaped. The pods are linear, slightly curved upward, longer than the stalks, rounded, biloc-ular, and 2-valved.
The plant is 2-3 ft. high, and flowers from May to June. It is perennial, and deciduous and herbaceous.
It has 4 honey-glands as in the Cuckoo - flower, and the honey forms into four drops in the middle of the flower, forming inwards,1 from the base of the short stamens. The drops lie between the long and short stamens, and at length fill the lower part of the space between the stamens and pistil, adhering firmly to it. There are none where the abortive or functionless stamens should be. The sepals in bud protect the parts, and being white, attract insects, and when the flowers open, they fall. The anthers open inwards, and the inner ones closely surround the stigma, and self-pollinate it, but honey and pollen seekers cross-pollinate it. The visitors are Hymenoptera (Apidae), Diptera (Syrphidae, Muscidae), Coleoptera (Nitidulidae, Curculionidae).
1 Causing, it may be, the sepals to drop early. This does not happen where the nectar is formed between the stamens and sepals, or outwards.
Photo. Rev. C. A. Ha!l - Sauce Alone (sisymbrium Alliaria, Scop.)
Jack-by-the-hedge is dispersed by its own agency. The dry pods curl and burst open, and the seeds are dispersed to some distance.
The plant is a sand plant and a humus-loving plant, and flourishes best upon a sand soil, in which there is a fair proportion of humus soil.
It thrives on sandstone formations, Keuper, and Liassic formations.
There are no fungal pests. A Hemipterous insect, Siphonophora alliarice, feeds on it.
Alliaria was an old genus proposed by Fuchs, derived from Allium, garlic, alluding to its smell.
This species is called Beggarman's Oatmeal, Cardiacke, Caspere, Eileber, English Treacle, Garlick-wort, Hedge-garlick, Jack-by-the-hedge, Leek-cress, Garlick Mustard, Penny Hedge, Poor Man's Mustard, Poor Man's Treacle, Sauce Alone, Swarms.
Once it was used as a vegetable and boiled with meat, hence the name Sauce Alone. It was fried in Wales with bacon and herrings. The garlic smell is most noticeable when the plant is rubbed between the fingers. It was employed as a sudorific, and for cancers and gangrene. The seeds were used to promote sneezing. It was reputed to be antiseptic.
Essential Specific Characters: 32. Sisymbrium Alliaria, Scop.- Stem tall, erect, leafy, leaves cordate, radical leaves reniform, dentate, sinuate, veined, strong-smelling, flowers white, small, pods longer than pedicels, seeds striate.