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.
Hardy and dominant, this plant has not been recognized in the early deposits preceding the present day.
It is confined to the Temperate Zone, and found in Europe, and N. and W. Asia. It is introduced in N. America. In Great Britain it is absent in N. Devon, in the Peninsula province; N. Hants, in the Channel province; E. Kent, in the Thames province; Bedford, in Anglia; W. Gloucs, Worcester, in the Severn province; in Wales, in Glamorgan, Pembroke, Cardigan, Carnarvon, Denbigh, Anglesea. In the Trent province it occurs in Leicester and Derby; in the Mersey province, not in Mid Lancs; in the Humber province, not in S.E. or N.W. Yorkshire; in the Tyne province, in Cumberland; not in Renfrew and Lanark in W. Lowlands; in Berwick, Haddington, Edinburgh, Linlithgow, Fife, West Perth, Forfar, S. and N. Aberdeen, Banff, Elgin, Easterness, Clyde Is., W. Highlands except Dumbarton, Ross, W. Sutherland, Hebrides as far north as Skye.
Burdock is a common weed found in waste places and on the borders of cultivated fields. It owes its wide distribution to its hardihood, and in the struggle for existence ousts, like many Docks and other quick-growing and sturdy plants, the smaller tenderer species.
This plant is tall and erect in habit. The species, as denoted by the specific name (minus), has leaves and flowerheads not so large as those of the other species.
The central stem is nodding, and with the branches bears scattered small heads, the terminal one being solitary. The leaves are heart-shaped, large, stalked, the radical leaves being coarsely toothed. The leaf-stalks are hollow, slightly angular, nearly round in section, and slightly furrowed.
The flowerheads are in a corymbose raceme on short stalks, globular, cottony, greenish, webbed in fruit, are slightly contracted at the mouth, and are not umbilicate. The phyllaries are not so long as the florets, awl-like, the inner row as long and gradually awl-like, more or less cylindrical. The upper part of the floret is as long as the lower. The fruit is brown with black blotches.
This plant may be 3-4 ft. high. It flowers in July and August. Lesser Burdock is biennial, and reproduced by seeds.
The tube of the corolla is narrow, the limb bell-shaped, with 5 slender lobes. The filaments are papillose. There is a long terminal appendage to the anthers, and the cells have a slender awl-like tail. The arms of the style are united below, downy below, blunt The throat of the corolla is 3 mm. long, the teeth erect, triangular, 1 mm. long. Honey is abundant, and lies in the tube to half the depth or more. The style arms are 1 mm. long, the papillae colourless, and the outer surface, which is of a violet colour, is covered with short, sharp hairs directed obliquely upwards. This prevents the honey being spoilt by rain or creeping insects, and has another significance also. For the hairs extend some way below where the forks of the style commence, and end in a ring of longer hairs. The style projects from the anther cylinder 1-2 mm. below the ring of longer hairs, and the 2 stigmatic lobes are spreading. Hence pollen cannot fall on the stigma, and the plant is usually cross-pollinated. The visitors are Bombus agrorum, Halictus longulus.
The burs are provided with hooks which catch in the coats of animals and are thus dispersed, the plant on recoiling shooting the burs a distance. The achenes are also provided with a pappus and can be dispersed by the wind.
A sandy soil in which there is some little humus best suits Burdock, which is to be found on a variety of rock soil, and may be frequently met with also on a clay soil.
A fungus, Puccinia hieracii, may be found on it, and it is galled by Tephritis bardanae.
The moths Agrotis rhomboidalis, Depressaria arenella, also the Ghost Swift (Hepialus humuli), Frosted Orange (Gortyna flavago), Argyrolepia badiana, Parasia lappella, Pterophorus galactodactylus, and the flies Trypeta cornuta and Chromatomyia nigra are found upon it.
Arctium, Dioscorides, is from the Greek arctos, bear, from the coarse texture of the involucres; and the second Latin name refers to the size of the heads. The plant has been used as a remedy for rheumatism.
Essential Specific Characters:168. Arctium minus, Bernh. - Stem tall, nutant, branched, leaves large, cordate, stalks hollow, flowers in rounded heads, purple, in raceme, on short stalks, phyllaries less than the florets.