Page:British Flowering Plants.djvu/37



The number of British genera is added in brackets after each family

CLASS I

DICOTYLEDONES

Seeds formed of two or more cotyledons. Stems formed of vascular tissue, sometimes enclosing pith, and surrounded by rind or bark. In trees the trunks are formed of concentric layers, one of which is supposed to be added every year. Leaves with branching and reticulating veins. Young plants always furnished with a tap-root. Flowers (when the corolla is present) with 4 or 5 petals (most frequently 5), rarely more.

I. Thalamifloræ}} Petals separate, and rising, as well as the stamens, near the ovary, and not from the calyx.

Order I. Ranunculaceæ (15 genera) These are herbaceous plants, with brightly coloured flowers. The calyx is always present; it has from 3 to 6 sepals, and is often brightly coloured, resembling a corolla. The corolla is sometimes composed of from 4 to 15 petals, in one or several rows, but is frequently rudimentary or absent. The stamens are numerous, and the anthers burst longitudinally. The carpels are usually numerous.

Though the flowers are attractive to insects, by which they are often fertilised, many of the plants belonging to this Order are extremely acrid, and frequently highly poisonous, though the poisonous principle is volatile, and may sometimes be dissipated by heat. 23