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.
Being strictly paludal this plant is one of those widely preserved in ancient deposits, as in Preglacial beds in Norfolk, Early Glacial beds in Norfolk, Interglacial beds at West Wittering, Late Glacial and Neolithic deposits. To-day it is found in Arctic Europe, Siberia, Dahuria, N. and W. India, N. America, in the North Temperate and Arctic Zones. It is found in every county of Great Britain except Hunts, and it grows at 1800 ft. in the Lake District.
The Bog Bean is a typical bog plant, growing only in the last resorts of the wild-fowler to-day, and not rarely surviving the drainage of its habitat wherever it grows. Damp hollows at the side of hills, wet meadows bordering streams, and true bogs or marshes are the places in which to search for this plant.
The habit is more or less prostrate. The rootstock is matted, stout, creeping. The stem is ascending, leafy, round in section. The leaves are ternate or 3-lobed, trifoliate (hence trifoliata). The leaflets are blunt, entire, with very short stalks, equal, inversely egg-shaped or oblong, wavy, the ultimate nerves having the tips free within the larger areoles. The sheath of the leaf-stalk is long and narrow, and not so long as the many-flowered scape.
The flowers are in a raceme with a leaf opposite it, white or pink, or flesh-colour, the upper surface of the corolla clothed with beautiful whitish filaments, or densely fringed within or bearded. The flower stalks are long, the ultimate ones short, stiff, spreading. The bracts are short, blunt, and broad. The sepals are oblong, blunt. The stamens are reddish. The capsule is blunt-pointed, many-seeded, the seeds small, polished.
Photo. B Hanley - Bog Bean (Menvanthes trifoliata, L.)
The plant is 1 ft. high. It flowers, when it does flower, which it does not always do, in July, but I have seen it in bud in April. The plant is perennial, propagated from cuttings, and worth cultivating.
Honey is secreted by the base of the ovary. The flowers are usually heterostylic or dimorphic, a long-styled and a short-styled form being found; but not everywhere, for in West Greenland plants of homomorphic type occur, with the pistil and stamens of the same length. No doubt the flower is rendered more conspicuous by the bearded surface of the corolla. The stamens, with purple anthers, are inserted on the tube, and the style is very slender, the stigma 2-lobed. The tube is somewhat funnel-shaped or bell-shaped, and accessible to most insects. The bearded filaments serve to keep out flies and protect the honey from the rain. The papillae of the stigma in the long-and the short-styled forms differ. So does the pollen, as in the Primrose. Few insects visit the flowers, as they grow in rather secluded spots, and are hidden under herbage, etc.
The capsule contains many seeds, dispersing them on opening partly by aid of the wind.
The leaves are attacked by a fungus, Protomyces menyanthii. Two moths, Spilosoma urticoe, the Light Knot Grass (Acronycta menyan-thidis), adopt the Buckbean as their food plant.
Menyanthes, Dioscorides, is from the Greek men, month, anthos, flower; and the second Latin name refers to the trifoliate leaves. Buckbean is from buckerbeane, Dutch bocks boonen. It is called Bean Trefoil, Beckbean, Bogbean, Bog Hop, Bog-nut, Brookbean, Buckbean, Marsh Claver, Marsh Cleever, Marsh Clover, Doudlar, Threefold, Bog, Marsh or Water Trefoil. It is called Bog Trefoil because of its clover-like leaves, and Bog Hop because of its well-known bitter properties and place of growth.
Bog Bean was said to be a tonic and febrifuge, or cure for fever. It has been used in place of Hops, and was formerly used for dropsy and rheumatism, whence its rarity in some districts. In Lapland they eat the powdered roots.
Essential Specific Characters: 212. Menyanthes trifoliata, L. - Stem ascending, terete, leaves tri-lobed, leaflets obovate, flowers pink, fringed.