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.
This species is found in the Cromer Forest Bed (Preglacial), in Interglacial beds, as well as in Roman deposits at Silchester. At the present day it is found in Arctic Europe, Northern Asia, that is to say, the Arctic Cold Temperate Zone. In the Peninsula province it occurs only in N. Somerset, and in Wales in Radnor, Pembroke, Cardigan, Montgomery, Merioneth. In North England it is not found in Cheviotland. It occurs in Scotland only in Kirkcudbright, Wigtown, Lanark, Berwick, Edinburgh, Fife, Argyle, Dumbarton, Clyde Islands, Caithness, and is rare, being local also in Ireland.
Meadow Rue grows by the sides of rivers, streams, and lakes, and is therefore a hygrophile and a plant of the lowlands. It is hardly a marsh plant in the usual sense, though it needs moisture; but it grows on banks where the soil is firm and never waterlogged. It grows above the line of Bur-reed, Flag, and Iris, with which it is associated, usually forming clumps, where the great Yellow Cress runs riot.
It is an erect plant, branched, with furrowed stems, having much the appearance of Clematis, but it is more compact in the distribution of the leaves and branches. It has a tufted habit, and grows in clumps of 2 or 3 ft. in area, in a more or less shrub-like manner. The leaves have the leaflets arranged each side of a common stalk.
Except Clematis this plant cannot be confused with any other British plant, and it differs from the Traveller's Joy in having no feathery appendage to its fruit, and in the absence of tendrils. The flower, sulphur-yellow, is made up of numerous feathery stamens and anthers. The leaves are smaller and closer.
Meadow Rue is 4 ft. high, flowering from May to July or August, and is a perennial, deciduous, herbaceous plant.
No honey is produced by the flowers, but abundant pollen; but though there are no petals and the sepals are very small, the stamens are many and conspicuous, and the plant is visited by pollen-seeking insects, Diptera (Syrphidae, Muscidae), Hymenoptera (Honey Bee).
The anthers open in the sun, closing in wet weather. The plant is autochorous, that is to say the achenes are dispersed by the plant's own agency. The achenes or fruit fall immediately around the parent stems.
This graceful plant is a sand-loving plant, growing on sandy soil, derived from sandy or silty beds, rarely mixed with clay or marl, chiefly alluvium,
Two species of cluster-cup fungus, or Puccinia, P. persistens and P. tha-lictri, grow on this plant, and it is galled by Ceci-domyia thalictri. Caterpillars of the moths, the Setaceous Hebrew character Noctua c-nigrum, and Red Sword - grass (Calocampa vetusta), feed on it.
The name Thalictrum is derived from the Greek thallos, a shoot, and was bestowed by Dioscorides. The specific name flavum is Latin for yellow. The English name Meadow Rue refers to its rue-like leaves.
This fine species is called False Rhubarb, Fen Rue, Meadow Rue, and Meadow Rhubarb.
The last name is bestowed because of its laxative properties, so Lyte says, and because the roots are yellow, like rhubarb.
When used with honey the leaves were said by Pliny to cure ulcers.
A dye has been made from the roots for dyeing wool, of a yellow colour.
The shoots have been used by country people in Bucks to boil in ale. Essential Specific Characters:-2. Thalictrum flavum, L. - Leaves radical, alternate, no involucre, panicle corymbose, flowers erect, sepals imbricate, 4-5, achenes with 1 pendulous seed, carpels awnless.
Photo. Dr. Somerville Hastings - Meadow Rue (Thalictrum Flavum, L.)