This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
The habitat of this plant is boggy meadows and copses, fens and marshes. The habit is climbing or trailing. The rootstock is creeping. The stem has herbaceous wings. The leaflets are in 2 or 3 pairs, linear-lance-shaped, acute, the leaf-stalks with 2 or more pairs, and a short, branched tendril, sword-shaped, with parallel nerves. The stipules are lance-shaped, half arrow-shaped. The flower-stalk is long, many- (2-6) flowered, longer than the leaves. The ultimate stalk is longer than the calyx-tube. The pod is stalked, linear-lance-shaped, flattened, hairless, netted, 6-8-seeded. The plant is 1-4 ft. high, flowering between June and August, and is a herbaceous perennial.
The habitat of this plant is river shingle. The stem is stout, leafy. The leaves consist of 6-8 wedge-shaped, oblong, blunt-pointed leaflets. The leafstalks are as long as the leaflets. The stipules are linear to narrow-pointed. The flowers are blue, in a long, partly whorled raceme. The bracts arc long, exceeding the buds. The upper lip of the calyx is divided into two nearly to the base, the lower is broad and 3-toothed. The corolla is blue or purple. The plant is more or less densely softly hairy, and very handsome. The plant is 1-2 ft. high, flowering in July and August, and is a herbaceous perennial.
The habitat of this plant is waste and cultivated ground, and the plant has been introduced. It is rare. It has been considered a variety of M. denticulata. The differences between it and the latter lie in the longer spines, which exceed the radius of the more or less rounded pod. The flowers are yellow, and are 1-4 on each stalk, in heads larger by twice than those of M. denticulata, with stronger spines and broader seeds. The pods are coiled 3-5 times, and have a thin edge. The spines are hooked, in 2 rows, spreading horizontally. The stipules are laciniate. The seeds are kidney-shaped. The plant flowers from May to August, and is a herbaceous annual.
The habitat of this plant is waste places. The plant is erect, slender, smaller than the other species. The leaflets are inversely ovate, coarsely toothed at the end. The stipules are awllike, entire. The flowers are very small, pale yellow, the wings and keel equal, shorter than the standard. The calyx-teeth are triangular, the calyx reddish-brown. The pods are round to ovoid, blunt-pointed, netted, smooth, and olive-green. The plant is from 6 in. to 1 ft. in height, flowering from June to August, and is a herbaceous annual.
The habitat of this plant is waste places, sandy and gravelly places, ballast heaps, railway banks, quarries, woods, plantations, cornfields, clover fields, etc. The habit is erect. The plant is not so robust as the Common Melilot. The leaflets are inversely ovate, the upper oblong, coarsely toothed, blunt. The stipules are awllike, entire. The flowers are white, in long racemes, small, the wings and keel equal, not so long as the standard. The pod is ovoid, acute, irregularly wrinkled, netted, smooth, blunt, black when ripe. The plant is 2-6 ft. high, flowering between June and August, and is a herbaceous biennial.