2nd. Orchella weeds having a flat (plane) or compressed thallus. These consist of R. fuciformis, and perhaps R. Montagnei.
Found in Angola (Portuguese Province on the West Coast of Africa); Madagascar; the Portuguese Province of Mozambique, from Cape Delgado to Delagoa Bay, on the East Coast of Africa; South America; and Pondicherry in India.
There is certainly a third description in commerce, known as mixed Orchella weeds, and consisting of varieties of the foregoing, mixed irregularly.
The second division of these Orchella weeds, R. fuciformis, is the more valuable, and is known in commerce, in its various forms, under the denomination of the country, as already stated, from which it is imported.
Angola Orchella weed; R. fuciformis. Thallus very flat, seldom exceeding an inch and a-half, or two inches, in length; in breadth (except at the fork or division) rarely more than one-sixth of an inch; colour greenish, or yellowish grey. As a dye stuff, it is the most valuable of all the Orchella weeds.
The above is Dr. Pereira’s description of the Angola Orchella weed, and the Mozambique Orchella weed is exactly the same; the Madagascar being smaller, but in other respects similar to the Angola and Mozambique.
Although the Portuguese have had possessions of immense territorial extent, both on the West and East Coasts of Africa, for more than three centuries, in regions where this weed of the most superior quality abounds, it is only within the last twenty or thirty years that they have brought it into the European market; and, from what I could learn at Mozambique, it is only since the Slave Trade was partially checked in that Province, that the Mozambique people began to export this valuable commodity, viz., subsequent to 1850. It abounds in such quantities along the whole of this coast, that literally fleets may be loaded with it.
As this work is written for practical purposes, I offer no apology for inserting what may hereafter be useful in developing the Resources of Eastern Africa.
Mode of extracting the colorific principles for transport. Dr. Stenhouse suggests the following method:—