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 recent distribution (of which alone anything is known) of this plant is circumscribed by the North Temperate and the Arctic Zones of Arctic Europe, North Africa, Western Asia. It is not found in Great Britain in S. Essex, Hunts, Carmarthen, Flint, Brecon, Radnor, Montgomery, Merioneth, Wigtown, Peebles, Selkirk, Mull, West Ross, northwards towards the Shetlands, but elsewhere generally, and ascends up to 2400 ft. in the Highlands, and is found in Ireland and the Channel Isles.
The Kidney Vetch is a lover of dry chalky soil or hill-sides, being largely a South of England plant, where also it grows by the sea; but it occurs in many other districts also as a well-established plant, especially in the vicinity of brickyards and similar places, where it is frequently associated with Sainfoin, Lucerne, and Hare's Foot Trefoil.
Herbaceous, tall, and having a silky appearance, this plant has a woody rootstock, suberect stem, with leaflets each side of a common stalk, with a larger terminal leaflet, bluish-white foliage (another English name, Lady's Fingers, may refer to the foliage). Anthyllis, meaning Beard Flower, refers to its silky appearance.
The flowers are yellow, lateral, and in pairs. The calyx is egg-shaped, with pointed teeth, membranous, exceeding the petals, the heads many-flowered, the flowers long-tubed. The pods are on long stalks, acute, smooth, netted, containing one seed.
This strikingly beautiful plant is from 6 in. to 1 ft. in height. It flowers in May right on up to August. It is perennial, and propagated by division.
The flower is like that of Lotus, with a long tube, and can only be reached by bees with a long proboscis. When the flower is young the stigma is dry though the keel encloses the pistil, and no pollen adheres, but when the bulk of the pollen has been removed the stigma is clammy, and pollen then adheres to it. The flower is pollinated by aid of the piston-mechanism, and the swollen and hairy calyx surrounds the long claws or stalks, the standard projecting 5-7 mm., and inclined upwards, with a groove on the lower part of the blade for the alae or wings, with two rounded lobes at its base. The wings or alae are, moreover, quite surrounded by the vexillum or standard.
Insects grasp the alae and insert their proboscis under the vexillum or standard. The alae surround the carina or keel, and it is forced down when the former are depressed. Each ala has a deep groove at its base, and the carina has a sharp knob fitting into this groove.
Photo. Flatters & Garnett - Kidney Vetch (Anthyllis Vulneraria, L.)
The upper margins of the alae are unfolded, wnence they remain close together. By this means the parts return to their place after the insect presses on them, causing pollen to be pressed into the slit, formed by the alar margins, by the thickened end of the stamens, the stigma remaining free from it; but if rubbed it becomes sticky and the pollen adheres. Hence insect visits favour cross-pollination. The pollen-grains are short, six-sided prisms with striated angles. The visitors are Bombus silvarum, B. hortorum, B. muscorum, Osmia, Lycaena.
The pod, enclosed by the dry, swollen calyx, is sometimes dehiscent, splitting open, and if the calyx persists the seed may be thrown to some distance by contraction of the pod.
Kidney Vetch is a lime-loving plant, being addicted to a lime soil, growing as a rule on chalk or other calcareous rocks.
This choice wild flower is infested by a cluster-cup fungus, Uromyces anthyllidis. A beetle, Tychius scheideri; a butterfly (the Mazarine Blue), a moth, Gelechia anthyllidella, and two Heteroptera, Lopus sulcatus, Hoplomachus thunbergi, feed on it.
Anthyllis, Dioscorides, is from the Greek anthos, flower, ioulos, down, from the silky bristles of the calyx, and Vulneraria because it was supposed to be a cure for wounds, from the Latin vulnus, wound.
Names applied to this plant include Cat's-claws, Crawnebs, Yellow Crow's-foot, Jupiter's Beard, Kidney Vetch, Lady's Fingers, Luck, Lamb's-toe, Staunch, Woundwort.
Being named Our Lady's Fingers, it was connected with Scriptural things. Gerarde says it "shall prevayle much against the strangury and the payne of the veynes ". It has been utilized as a yellow dye. The excellence of South Down mutton has been ascribed to the prevalence of this plant in the pastures where sheep feed in the south, and it is undoubtedly a good fodder plant. The colour of the flower varies considerably according to the nature of the soil.
Essential Specific Characters:83. Anthyllis Vulneraria, L. - Stem erect, radical leaves simple, oblong, upper pinnate, leaflets unequal, glaucous, terminal leaflet largest, flowers yellow, in a dense head, two on each stalk, calyx inflated, woolly, bracts large.