VEGETABLE DYES 113 
The second group of adjective dyes, the “ flavone ’’ 
group, include by far the largest number of vegetable 
dyes. All these dyes are built upon the same skeleton 
“ flavone ’’ with slight modifications in the number and 
‘position of the hydroxyl groups in the molecule. They 
produce a range of shades of yellows and browns, and 
are very widely distributed in the vegetable kingdom. 
For yellows the plants generally used were: 1. Weld 
from Reseda luteola, once cultivated in France, Ger- 
many and Italy. 2. Old fustic, the wood of a Central 
American tree Morus tinctoria. 3. Young fustic from 
the Rhus Cotinus of Southern Europe and the West 
Indies. 4. Quercitron from the inner bark of Quercus 
nigra and Q. tinctoria of the United States and Central 
America; while the ling, Calluna vulgaris, i is still used 
by the Highlanders on an alum mordant. The tips 
are gathered just before flowering, boiled in water, and 
the liquor used for dyeing. 
Although these plants all give fast good yellows, 
there are so many cheap yellow synthetic dyes that they 
are hardly likely to survive. Fustic wood can still be 
bought, and is used for compound shades. 
The closely allied brown dyes are more likely to hold 
their own because in many cases they give fine perma- 
nent colours. Catechu gives a brown on cotton, mor- 
danted with copper sulphate and later ‘‘ saddened ” in 
potassium dichromate ; which is fast to light, soap, and 
even bleaching. It is used also for compound shades 
and weighting black silks and woollens. The dye is 
obtained from the heartwood of Acacia Catechu or 
Areca Catechu from Bengal, and also from the leaves 
of the mangrove Ceriops Candolleana. The leaves are 
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