416 THE WO AD AND WELD CROPS. 



digo has virtually superseded the use of woad in the 

 dyeing of vegetable blues, still a certain demand exists 

 for woad, which is used frequently in combination with 

 indigo for certain tints, and also as a basis for blacks and 

 other colours. 1 



Woad belongs to the order CRUCIFER^E, which furnishes 

 so many important and valuable plants to the agriculture 

 of this country. It constitutes the distinct genus ISATIS, 

 the species cultivated in this country being the I. TINC- 

 TORIA, or DYER'S WOAD. In China, another species, the 

 /. indigotica, is largely grown for the same purposes in 

 the northern provinces, where the true indigo 2 cannot be 

 cultivated. 



The plant is a biennial, growing to the height of 3 to 

 4 feet, with succulent, smooth, glaucous leaves, the upper- 

 most being heart-shaped at the base. The flowers, which 

 are small and of a golden-yellow colour, are arranged in 

 panicles, branching, and are succeeded by dark-coloured 

 short pods, opening into two valves, each of which contains 

 a single seed. It is frequently met with growing wild 

 about fields and cultivated places, and is supposed to be 

 a native plant, although no really wild habitation could 

 now be pointed out for it. 



The range of soils in which woad can be successfully 

 cultivated is limited to those of the richest description. 

 Deep friable loams containing large quantities of organic 

 matter, as the fen lands of Lincolnshire and Huntingdon- 

 shire, the rich alluvial bottoms of valleys, or along the 

 course of the slowly running rivers, which are met with 

 in the western and in the east midland counties, are those 

 alone in which its cultivation is now attempted to be car- 



1 Much curious and interesting information in regard to the introduction of 

 indigo, and the circumstances attending it, is given in Beckmann's History of 

 Inventions. See also Schrebers, Seschreibung des Waidtes, Halle, 1752. 



2 Indigo is produced by the Indigofera tinctoria and /. coerulea, both plants 

 belonging to the papilionaceous sub-tribe of the order Leguminosce. 



