This section is from the book "Wayside And Woodland Blossoms", by Edward Step. Also available from Amazon: Wayside And Woodland Blossoms: A Guide To British Wild-Flowers.
Ranunculus ficaria. - Ranunculaceae. The petals are united for half their length to form a tube, and the five free lobes are oblique. The structure and arrangement of the stamens and pistil are very curious, and evidently have relation to cross-fertilization by insects, for the throat of the corolla-tube is closely guarded by a fringe of silky hairs, impassable by the thrips that vainly haunt the mouth in quest of pollen. The plant rarely, if ever, produces seed in this country, and this indicates that the insects necessary to its fertilization are not British. Flowers, April and May, and sparingly throughout the year.
As soon as there comes a slackening of the iron rule of winter, whether it be early in February or late in March, then on sunny banks and at the feet of pasture-hedges, or on waste-ground by the roadside, the burnished gold stars of the Lesser Celandine glitter in the wintry sunshine. It is a charming little plant in its brightness and compactness, and not in the least suggestive of weediness; yet, if introduced into the garden it can become an absolute nuisance. Its roots produce a large number of cylindrical tubers, which - when the "doctrine of signatures" was in fashion - were held to resemble hemorrhoids, and therefore to be medicinal for that painful malady.: hence one of its folk-names - Pilewort. Each of these tubers is capable of producing a new plant, and reproduction by this method is speedily effected.
Lesser Celandine. Pilewort.
The leaves vary much in shape and in size. The larger, from the root (radical), are more or less heart-shaped, the edges bluntly angled; the smaller ones, from the stem (caudal), may approach towards the form of an ivy-leaf. The sepals (calyx) vary from three to five, usually three, and the petals from seven to twelve. The stamens are numerous, as also are the carpels or divisions of the fruit. As in the Anemone (page 3), these are achenes, a form persistent throughout the genus Ranunculus; each contains a single seed. The plant is well distributed throughout the country, and may be found in flower until May.