dock; a genus of the trigynia order, be- longing to the hexandra clas of plants. There are 27 species, of which the most remarkable are,

1. The patientis, commonly called patience rhubarb. This was formerly much more cultivated in the British gardens than at present: the roots of this have been generally used for the monk's rhubarb, and has even been thought to be the true kind; but others suppose the second sort should be used as such. The root is large, and divides into many thick fibres; their outer cover is brown, but they are yellow within, with some reddish veins; the leaves are broad, long, and acute-pointed; their footstalks are of a reddish colour; the stalks rise six or seven feet high, and divide to- wards the top into several erect branches garnished with a few narrow leaves terminating with loose spikes of large staminate flowers. These appear in June, and are succeeded by pretty large three-cornered seeds, whose coverings are entire, which ripen in autumn.

2. The alpinus, or monk's rhubarb, grows natu- rally on the Alps, but has long been cultivated in the gardens of this country. This hath large roots which spread and multiply by their offsets; they are shorter and thicker than the former, are of a very dark brown on the outside, and yellow within. The leaves are of the round heart-shape, standing upon long footstalks. The stalks rise from two to three feet high; they are thick, and have a few small roundish leaves on the lower part; but the upper part is closely garnished with spikes of white flowers standing erect close to the stalks. These appear in the latter end of May, and are succeeded by large triangular seeds which ripen in August.

3. The aquaticus, or water-dock, grows naturally in ponds, ditches, and standing waters, in many parts of Britain. It is supposed to be the herba Britannica of the ancients. It hath large roots which strike deep