3o8 FORESTRY OF WEST AFRICA. 



are three inches long. — 'History of Dichlamydeous 

 Plants,' G. Don, vol. ii., p. 365, &c. 



Distribution : Upper Guinea, Nile Land. 



Trifolium subrotundum, Steud. — Perennial, culti- 

 vated in the Nile Land under the name of " Mayad " 

 as a forage.— ' Flora of Tropical Africa,' D. Oliver, 

 vol. ii., p. 59, 



Distribution: Upper Guinea, Nile Land, Lower 

 Guinea. 



Indigo {Indigofera tinctoria, L.). — ^A copiously- 

 branched shrub, four to six feet high, largely used as 

 a dye by the natives of the Upper Gambia. Indigo of 

 commerce is chiefly obtained from two species of 

 Indigofera, viz., /. tinctoria, L., and /. Anil, L. In 

 the preparation of indigo the plants are cut down 

 just before the flowering stage. They are then closely 

 pressed into a trough or vat, and covered with water. 

 Fermentation then takes place, and is allowed to 

 continue from twelve to fifteen hours. The plants 

 are then removed, and the water is stirred and beaten 

 with paddles, when its colour passes to a blue, and 

 the sedimentary matter sinks to the bottom ; the 

 supernatant liquid is drawn off, and the residue, after 

 being heated, is washed and filtered. After this 

 process it is pressed into cakes — usually cubical — 

 dried and stamped, and is then ready for the market. 

 The use of indigo as a dye is of great antiquity, 

 and is chiefly imported into this countiy for that 



