What is "sium sisarum"

Skirret \Skir"ret\, n. [A corrupted form equivalent to sugarwort.] (Bot.) An umbelliferous plant ( Sium Sisarum syn. Pimpinella Sisarum). It is a native of Asia, but has been long cultivated in Europe for its edible clustered tuberous roots, which are very sweet.

Sium sisarum, commonly known as skirret, is a perennial plant of the family Apiaceae sometimes grown as a root vegetable. The English name skirret is derived from the Middle English 'skirwhit' or 'skirwort', meaning 'white root'. In Scotland it is known as crummock. Its Danish name sukkerrod, Dutch name suikerwortel and German name "Zuckerwurzel" translate as 'sugar root'.

Skirret has a cluster of bright white, sweetish, somewhat aromatic roots, each approximately 15-20 cm in length. These are used as a vegetable in the same manner as the common salsify, black salsify and the parsnip.