SIUM, WATER PARSNEP, in botany: A genus of plants belonging to the class of pentandria, and order of digynia, and in the natural system ranging under the 45th order, Umbellata. The fruit is a little ovated, and streaked. The involucre is polyphyllous, and the petals are heart-shaped. There are 12 species; the latifolium, angustifolium, nodiflorum, sifarum, ninsi, rigidus, japonicum, filicularia, gracum, sicalum, repens, and decumbens. The three first are natives of Britain. 1. The latifolium, or great water-parsnep, which grows spontaneously in many places both of England and Scotland on the sides of lakes, ponds, and rivulets. The stalk is erect and furrowed, a yard high or more. The leaves are pinnated with three or four pair of large elliptic pinnæ, with an odd one at the end, all serrated on the edges. The stalk and branches are terminated with erect umbels, which is the chief characteristic of the species. Cattle are said to have run mad by feeding upon this plant. 2. The angustifolium, or narrow-leaved water-parsnep, has pinnated leaves; the axillary umbels are pedunculated, and the general involucre is pinnatifid. It grows in ditches and rivulets, but is not common. 3. The nodiflorum, reclining water-parsnep, has pinnated leaves, but the axillary umbels are sessile. It grows on the sides of rivulets.
The sium sifarum, or skirret, is a native of China, but has been for a long time cultivated in Europe, and particularly in Germany. The root is a bunch of fleshy fibres, each of which is about as thick as a finger, but very uneven, covered with a whitish rough bark, and has a hard core or pith running thro' the centre. From the crown of this bunch come several winged leaves, consisting of two or three pair of oblong dentated lobes each, and terminated by an odd one. The stalk rises to about two feet, is set with leaves at the joints, and breaks into branches towards the top, each terminating with an umbel of small white flowers, which are succeeded by striated
Six-clerks feeds like those of parsley. Skirrets come nearest to parsneps of any of the cuculent roots, both for flavour and nutritive qualities. They are rather sweeter than the parsnep, and therefore to some few palates are not altogether disagreeable.
Mr Margraaf extracted from lb. of skirret root ounces of pure sugar.