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.
This common buttercup is found in Arctic Europe, parts of Asia, Africa, and has been introduced into America. It is found in every part of the British Isles, up to nearly 3000 ft. in Scotland. The usual habitat is wet meadows, and almost ever)' roadside ditch contains it, whilst moist open parts of woods also form a suitable spot for it. The habit is procumbent or trailing'. The stem is provided with creeping stoles or underground runners, from an erect main stalk, with fibrous roots. It is usually found in patches for this reason. The essential characters are the furrowed flower stalk, and the erect sepals. The receptacle is hairy. The lower part of the stem is often purple. It is about a foot high, and is a perennial, flowering in May till August. The pollination is like that of the Upright Meadow Buttercup (q.v.). The seeds are dispersed like those of the latter. The soil is a loamy clay. The plant is poisonous, being bitter, causing blisters.
The range of this buttercup is the same as that of the Creeping Buttercup. It occurs in all but six of the counties of the British Isles. In some meadows this form is the dominant buttercup early in the year, studding the earth profusely with its golden cups. It is found indifferently in both meadows and pastures. The habit is of the rosette type. The stem is bulb-like at the base, the leaves are chiefly radical leaves, the stems erect. The flower-stalks are furrowed and smooth, the sepals turned back. It flowers in May, and is perennial. The plant is a foot high. The pollination and dispersal are as in the last, the anthers ripening first, the honey-glands being at the base of the petals. The plant is a sand-lover.