What is "allium fistulosum"

Welsh \Welsh\, a. [AS. w[ae]lisc, welisc, from wealh a stranger, foreigner, not of Saxon origin, a Welshman, a Celt, Gael; akin to OHG. walh, whence G. w["a]lsch or welsch, Celtic, Welsh, Italian, French, Foreign, strange, OHG. walhisc; from the name of a Celtic tribe. See Walnut.] Of or pertaining to Wales, or its inhabitants. [Sometimes written also Welch.]

Welsh flannel, a fine kind of flannel made from the fleece of the flocks of the Welsh mountains, and largely manufactured by hand.

Welsh glaive, or Welsh hook, a weapon of war used in former times by the Welsh, commonly regarded as a kind of poleax.
--Fairholt.
--Craig.

Welsh mortgage (O. Eng. Law), a species of mortgage, being a conveyance of an estate, redeemable at any time on payment of the principal, with an understanding that the profits in the mean time shall be received by the mortgagee without account, in satisfaction of interest.
--Burrill.

Welsh mutton, a choice and delicate kind of mutton obtained from a breed of small sheep in Wales.

Welsh onion (Bot.), a kind of onion ( Allium fistulosum) having hollow inflated stalks and leaves, but scarcely any bulb, a native of Siberia. It is said to have been introduced from Germany, and is supposed to have derived its name from the German term w["a]lsch foreign.

Welsh parsley, hemp, or halters made from hemp. [Obs. & Jocular]
--J. Fletcher.

Welsh rabbit. See under Rabbit.

Cibol \Cib"ol\, n. [F. ciboule, LL. cepula, cepola, dim. of L. cepa, caepa, caepe, an onion. Cf. Chibbal, Cives.] A perennial alliaceous plant ( Allium fistulosum), sometimes called Welsh onion. Its fistular leaves areused in cookery. [1913 Webster] ||

Allium fistulosum L. (Welsh onion, Japanese bunching onion, bunching onion) is a species of perennial onion. The common name Welsh onion is rather a misnomer, as the species is native to China, though cultivated in many places and naturalized in scattered locations in Eurasia and North America.

The species is very similar in taste and odor to the related common onion, Allium cepa, and hybrids between the two ( tree onions) exist. The Welsh onion, however, does not develop bulbs, and possesses hollow leaves (fistulosum means "hollow") and scapes. Large varieties of the Welsh onion resemble the leek, such as the Japanese negi, whilst smaller varieties resemble chives. Many Welsh onions can multiply by forming perennial evergreen clumps. Next to culinary use, it is also grown in a bunch as an ornamental plant.

Historically, the Welsh onion was known as the cibol. In Cornwall, they are known as chibbles.

A. fistulosum is not indigenous to Wales or particularly common in Welsh cuisine (the green Allium common to Wales is the leek, A. ampeloprasum, the national vegetable of Wales). "Welsh" preserves the original meaning of the Old English word welisc, or Old German welsche, meaning "foreign" (compare wal- in "walnut", of the same etymological origin).