Darwin is describing crops on a farm:
"Mandioca or cassada is likewise cultivated in great quantity. Every part of this plant is useful; the leaves and stalks are eaten by the horses, and the roots are ground into a pulp, which, when pressed dry and baked, forms the farinha, the principal article of sustenance in the Brazils. It is a curious, though well-known fact, that the juice of this most nutritious plant is highly poisonous."
The "mandioc or cassanda" is evidently Portuguese for
manioc or cassava" a kind of winter melon. I was surprised to find that "farina" is not always ground cereal grain:
farina
n.
5ME < L, ground grain, meal < far, sort of grain, spelt < IE base *bhares3 > OE bere, BARLEY6
1 flour or meal made from cereal grains (esp. whole wheat), potatoes, nuts, etc. and eaten as a cooked cereal
2 potato starch or other starch

Is a winter melon the same thing as a root vegetable, Dr Bill? We discussed cassava in a recently revived thread (something to do with Jimmy Hoffa [??]). Anyway, farinha means "flour," but often when you use the term in "the Brazils" without qualifying it, cassava/manioc is inferred.

Dear AS: Darwin speaks of roots being ground. Doesn't make sense to me to speak of a melon having edible roots. I was surprised to find "Casava" originally name of a place in Turkey.
casaba
n.
5after Kasaba, former name of Turgutlu, Turkey, whence the melon came6 any of a group of cultivated melons (Cucumis melo var. inodorus) with a hard, yellow rind and sweet, usually white flesh; winter melon

Just to confuse things further, look at definition of "tapioca":
tapioca
n.
5Port & Sp < Tupi & Guarani typyoca < tipi, dregs + ok, to squeeze out6
1 a starchy, granular substance prepared from the root of the cassava plant, used to make puddings, thicken soups, etc.
2 pudding made from this substance

"If you're not confused, you just don't understand the situation."

Now I get it: There's casaBa melon and cassaVa root. Different etymological roots, as it were, yes? What I'm talking about is the root vegetable.

But Darwin said the farinha was made from "winter melons"
I thought at first that the difference between "b" and "v" might be from Porutuguese spelling, but I know you would know about that.
I can remember when some sportswriters called baseballs
casabas, perhaps because batter was from S.A.

No definition of winter melon I've found would seem to indicate anything that might could get made into farinha.

Mandioca or cassada is likewise cultivated in great quantity. Every part of this plant is useful; the leaves and stalks are eaten by the horses, and the roots are ground into a pulp, which, when pressed dry and baked, forms the farinha, the principal article of sustenance in the Brazils. It is a curious, though well-known fact, that the juice of this most nutritious plant is highly poisonous."


The same plant is grown in many part of sub saharian africa, (and called foo-foo, and various other names. the root is poisonous, too, and is only edible after it has been soaked in water, then dried, then ground (or mashes) and then soaked and cooked. the plant is rich n cyanide, and even with the treatment, it still is rich in cyanide, and it is a very poor quality food.

still, its a major food for millions of people.