The species of this Order are nearly all extra-tropical. In India, a few only have as yet been found on the plains, but there are a considerable number natives of the higher hills.
The members of this family are for the most part readily distinguished by their habit, and by the analogy of their organization. The calyx; consists of several distinct, deciduous sepals, often coloured, or petaloid, and in the absence of petals performing the functions of both organs; in number, varying from 3 to 15, the estivation, generally, imbricating, but sometimes valvular, or with the edges folded in, as in Clematis. Corolla; sometimes wanting, as in most of the species of Clematis and Thalictrum, or composed of from 5 to 15 distinct petals. Stamens; usually numerous, anthers adnate, opening outwardly, inserted with the petals below the pistils. Pistils; usually united in form of a head in the centre of the flower; ovaries, each, one celled, with a single ovule, (aechnia) or many seeded and capsular, as in Aconite and some others; style always lateral, sometimes very long and plumose. Seeds albuminous, when solitary, either erect, or pendulous from the apex of the cell. Embryo minute, enclosed in a horny albumen. Plants, usually, herbaceous, with exsti-pulate leaves, sheathing at the base, generally, much divided; more rarely, scandent shrubs : the hairs, when present, simple.
Though generally an easily recognised order, the Ranunculaceae have strong affinities with some other orders, which however, differ widely among themselves. I do not think it necessary to indicate here their more remote and less striking affinities, but will briefly mention a few of their nearest allies.
With Dilleniaceae and Magnoliaceae, they associate in the position, number and structure of their parts of fructification ; but from the former, they are separated by the want of an aril to the seed, their deciduous calyx, and generally, by their very different habit. This last distinction is however weakened, through the twining habit of Tetracera and Delema associating them with the fruticose and scandent genera Clematis and Naravelia, while the herbaceous habit and sheathing leaves of Acrotrema, associate it with the more common herbaceous forms. From Magnoliaceas they are readily distinguished by the absence of stipules, difference of sensible qualities, and habit. With Rosaceae, though differing toto coelo in their sen-