1911 Encyclopædia Britannica/Cassava

CASSAVA, the name given to the farinaceous root of two species of Euphorbiaceous plants, the bitter cassava, Manihot utilissima, and the sweet cassava, M. Aipi, both highly important sources of food starches; Manihot is given as the native Brazilian name in Spanish writings of the 16th century. They are herbaceous or semi-shrubby perennials with very large fleshy, cylindrical, tapering roots as much as 3 ft. long and 6 to 9 in. in diameter, and filled with milky juice. The slender stems, 5 to 9 ft. high, bear large spreading long-stalked leaves, with the blade divided nearly to the base into three to seven long narrow segments. The plants are probably natives of South America, but the bitter cassava, which is the more important of the two in an economic sense, has been introduced into most tropical regions, and is extensively cultivated in west tropical Africa and the Malay Archipelago, from which, as well as from Brazil and other South American states, its starch in the form of tapioca is a staple article of export. The sap of the bitter cassava root contains hydrocyanic acid, and the root, being therefore highly poisonous, cannot be eaten in a fresh condition; while on the other hand the sweet cassava is perfectly innocuous, and is employed as a table vegetable. Exposure to heat dissipates the poisonous principle, and the concentrated juice is in that state used as the basis of cassareep and other sauces. From the bitter cassava roots many different food preparations are made in Brazil. The roots are preserved for use by being simply cleaned, sliced and dried; from such dried slices manioc or cassava meal, used for cassava cakes, &c., is prepared by rasping. The starch also is separated and used for food under the name of Brazilian arrowroot; and this, when agglomerated into pellets on hot plates, forms the tapioca (q.v.) of commerce. Cassava starch has a stellate hilum, which readily distinguishes it under the microscope from other starches.

Cassava EB1911 p457.png
Cassava or Manioc (Manihot utilissima), less than half nat. size.
1, An inflorescence showing at a
  a fruit which will presently
  separate into five one-seeded
  parts, about 1/2 nat. size.
2, Pistil of female flower.
3, Stamens and fleshy disc of male
4, Seed with its appendage
  (strophiole or caruncle).