APIUM, or PARSLEY, in botany, a genus of the pentandria digynia class. The fruit is of an oval shape and streaked; the involucrum consists of one leaf; and the petals are inflected. There are only two species of apium, viz. the petroselinum, a native of Sardinia; and the graveolens, a native of Britain. The seeds of the petroselinum are carminative, and the root is used as an aperient.