Saw-Wort, or Serratula, L. a genus of plants, comprising 18 species; two of which only, according to Dr. Smith, are indigenous ; namely :
1. The thicioria, or Common Saw-wort, is perennial; grows in woods and on pastures, where it flowers in the month of July. - This plant is employed by dyers, to impart a yellow colour; but, being inferior to the Dyers-weed, its use is chiefly confined to the coarser woollen cloths, and as an ingredient in other dyeing drugs. - In combination with indigo, the Common Saw-wort strikes a per-green colour. Its leaves readily yield a brownish-yellow decoction, which, on diluting it with water, changes to a brighter tinge ; and, by adding a solution of pure pot-ash, acquires a darker shade : but, on dropping into it a little of the spirit of sal-ammoniac, becomes reddish-brown; which may again be rendered of a golden tint, by the addition of pure water. On the whole, Porner observes, thatalum and gypsum appear to be best calculated for extracting a fine yellow colour from this plant; which the Germans industriously cultivate. - Goats eat this species, but horses do not relish it; and it is totally refused by sheep, hogs, and cows.
2. The arvensis, Corn Saw-wort, or Way-thistle, thrives in corn-fields and on road-sides: it flowers in the month of July ; and is often a very troublesome weed. - When burnt, the ashes of this plant yield a very pure vegetable alkali, or pot-ash; on which account it deserves to be propagated in the vicinity of glass-houses and soap manufactories. - Neither cows, horses, nor swine eat this vegetable ; but it is relished by goats : its young and tender tops are occasionally devoured by horses. - While young, the Way-thistle is eagerly consumed by sheep : when bruised, and mixed with bran, this weed affords excellent food for every species of cattle. Its seeds are enveloped in large downy crowns; which, according to Bechstein, ' may be advantageously combined with wool, and thus converted into blankets and coarse cloth: nor are they less useful for stuffing pillows, bolsters, and mattresses.