CLASS XV. OIIDER I.J ISATIS. 875 



possess strong calliartic properties; but it clors not appear to liaveLcen 

 applied to any particular use or esteemed amongst us of any value 

 either medicinally or olLcrwise. 



GENUS III. ISA'TIS— Linn. JVoad. 



Nat. Ord. Crucjf'er^. Juss. 



Gen Char. Silicula oblong, laterally compressed, one celled, of two 

 keeled valves, one seeded. Seeds wiili the cotyledons incumbent. 

 — (e Fig. 2, page 872) — Name isrocT»j, of the Greeks. 



1. I. tinclo'ria, Linn. (Fig. 1007.) Di/er^s Woad. Silicula oblong, 

 obtuse, or emarginated, tapering to the base ; radicle leaves oblong, 

 crenate, petiolate, those of the stem sessile, sagittate, entire. 



English Botany, t. 97. — English Flora, vol. iii. p. 182. — Hooker, 

 British Flora, ed. 4. vol. i. p. 246. — Lindley, Synopsis, p. ;J2. 



Root tapering. Stem erect, from two to three feet high, simple, 

 leafy, a glaucous green, smooth. Leaves numerous, smooth, a glaucous 

 green, paler beneath the radical ones, large, oldong, ovate, peiiolated, 

 crenated or waved on the margin, those of the stem sessile, entire, 

 with two lanceolate arrow-shaped lobes at the base. Inflorescence a 

 terminal panicle, of numerous divided branches, with a bractealed leaf 

 at the base of each. Flowers numerous, yellow, in crowded racemes. 

 Calyx of four ovate equal concave spreading deciduous pieces, yellow. 

 Corolla of four equal obovate spreading petals, tapering at the base 

 into a short claw. Stamens \\\\.\\ simple filaments and small roundish 

 yellow anthers. Stigmas sessile, capitale. Fruit an oblong obtuse or 

 emarginated silicula, tapering towards the base, pendulous, smooth and 

 shining, almost blark, one celled, two valved, keeled. Seed solitary, 

 pendulous from the top of the cell. 



Habitat. — Cultivated fields about Ely, Durham, Leicester, &c., 

 but rare. 



ISiennial; flowering in July. 



Woad appears from a very early period to have been used as a dye; 

 according to Pliny, the Greeks and Romans used it ; and he says also 

 that the ancient Britons used it for painting their bodies. The leaves 

 afford, when fermented, a blue colouring matter, the same as indigo, 

 but in a much smaller proportion than the leaves of the Indigoferae 

 plants, which are grown in the greatest abundance and success in the 

 East and West Indies, where they form an important article of export ; 

 and on account of the plants producing so much greater a proportion 

 of colouring matter than the Woad, as well as beinggrown at so much 

 less expense, their cultivation in England is entirely given up. Woad 

 was formerly a plant of considerable commercial importance, and 

 was cultivated in many parts of the country, especially in Somerset- 



