104 EXPLOITATION OF PLANTS 
Among natural dyes there are only three which will 
dye vegetable fabrics directly, namely, turmeric, saf- 
flower and annatto. 
Turmeric is a bright yellow dye, which may be used 
for cotton, silk, or wool dyeing. It is made from the 
ground-up rhizome of Curcuma tinctoria. 
Safflower is obtained from the flower-heads of the 
Egyptian thistle, Carthamus tinctoria. These contain 
two dyes, a fugitive yellow, which is one of the most 
ancient vegetable dyes, and also small quantities of a 
bright pink, which was formerly used in all the coun- 
tries of Europe to dye red tape. 
Annatto comes from the pulpy seed-coat (aril) of the 
shrub Bixa Orellana, and gives a bright orange colour. 
Since the discovery of Congo Red in 1884, a number 
of direct cotton dyes have been prepared from coal tar 
with a wide range of colours. They are all fugitive, 
and are not fast to hot water; but they are extensively 
used for cheap calico printing. The natural dyes, 
being equally fugitive, possess no essential advantages 
over them and cannot, with their limited colour range, 
hope to compete successfully with the synthetic dyes. 
Several direct dyes for silk or wool only were formerly 
used ; but as they have now been superseded by arti- 
ficial substitutes, they need: not be considered here. 
There is, however, one interesting group of direct wool 
dyes, which might be capable of more extensive exploita- 
tion. These are the lichen dyes. 
Lichen dyes—In general the dye-producing lichens 
are drab-coloured species growing on rocks or trees in 
the most exposed places, especially in bleak mountain- 
ous districts, or near the sea coast. They occupy 
