106 ON THE PRESENT USE OF LICHENS AS DYE-STUFFS. 
first, and especially the corticolous, Everniiform, narrow, or linear con- 
ditions thereof, which affect the bark and branches of Dalbergia melan- 
ozylon, Mangifera Indica, and other tropical littoral trees. 
The principal geographical sources of the “ Orchella weeds” are in— 
. Africa. A. East coast and islands: Mozambique ; Madagascar 
(Island) ; Zanzibar (Island) ; Mauritius (Island). B. West coast and 
islands: Angola; Benguela; Loango; Sierra Leone; Cape Verde 
(Island) ; Teneriffe (Island) ; Madeira (Island) ; St. Thomas (Island), 
Prince’s (Island), Gulf of Guinea. C. South coast : Cape Colony. 
IL. South America. A, East coast: Brazil, Rio Janeiro. B. West 
coast; Chili, Valparaiso; Peru, Lima; Ecuador, Guayaquil. C. North 
coast and islands ; Curaçao (one of the Antilles Islands). III. Asia. 
A. India and the Indian islands : Burmah; Bombay ; Ceylon (islands); 
Timor (island). 
urton thus arranges the principal kinds, known at present in the 
London market, in the order of their commercial value :—1. Mozam- 
bique. 2. Ceylon. 3. Angola. 4. Lima, Bombay, equal. 5. Cape 
Verde. 
In general terms, it may be stated that the finest tinctorial forms 
are equatorial, growing within the limits of 10° north and south of 
the Line; while the Rocce/le are both few in number and inferior in 
quality beyond 30? on either side of the equator. "This excludes 
Europe and North America wholly, Asia in great measure, and the 
French provinces of Northern Africa—as ial sources of valuable 
“‘Orchella weeds." These weeds are to be found greatly beyond the 
limits of 30° north and south ; for instance, in the Cape Colony and on 
the Mediterranean shores, and they extend as far north as the Channel 
Islands, the southern coast and islands of England, and the Frith of 
Clyde islands in Scotland. But in Britain and other temperate coun- 
tries they occur in insufficient amount to be of any practical value. 
Central or tropical Africa, and Southern America and Asia, with their 
respective islands, constitute a field of supply of the most valuable 
kinds, of which, as yet, only an insignificant portion has been ren- 
dered available. In the International Exhibition of 1862, samples of 
* Orchella weeds" from the following new commercial sources were 
shown : Ceylon, Central and Southern Africa, including Natal. 
The principal European importers of “ Orchella weed " appear at 
present to be the Portuguese, French, and English. The imports into 
