644 CONTEIBUTIONS FROM THE NATIONAL HEEBAPJUM. 



agria" (Cuba); " caxcamote " (Guatemala); "quiscamote" (Honduras); 

 "guacamote" (Oaxaca, Consatti). 



Cassava* is one of the valuable food plants of the world, and the most 

 important one in many tropical regions, taking the place of corn and wheat. 

 It is much cultivated in some parts of Mexico, especially in the Yucatan Penin- 

 sula, and is said to have been introduced in preconquest times. The plants 

 are grown from cuttings. Two well-marked varieties occur : One may be used 

 without special treatment ("yuca dulce") ; the other has very poisonous juice, 

 the injurious principle of which is made harmless by heat. The poisonous 

 properties have been attributed to hydrocyanic acid, but others claim that they 

 are due to a peculiar principle, manihotoxine. Meal, starch, and cassava or 

 tapioca are obtained from the roots. The first is prepared by peeling and grat- 

 ing the root, expressing the juice, and drying and sifting the meal, which must 

 also be heated in the case of the poisonous variety. Starch is obtained by pre- 

 cipitation from an infusion of the grated roots. Tapioca is prepared by roast- 

 ing the starch grains. The roots of the cassava plant also furnish a useful 

 food for stock of all kinds. Cassaripe, the thickened gum obtained from the 

 root of yuca agria, has antiseptic properties and is commonly used in Brazil for 

 the pi-eservation of meat. The Caribs prepared an intoxicating liquor from the 

 roots. According to Barham, the fresh roots, when eaten, cause pain in the 

 stomach, swelling of the abdomen, violent vomiting and purging, giddiness, 

 chills, dimness of vision, and in a few hours death. 



The cassava plant is treated at great length by Oviedo (Lib. VII, Cap. II) as 

 well as by most other early writers upon tropical American natural history. 

 He describes the method of cultivation with considerable detail. The yuca 

 dulce, he states, was not known in the islands. He asserts that the yuca agria 

 is poisonous to all animals except cows, horses, and rats, and that " a small 

 draught of the juice will kill an elephant or any other animal or man." He 

 does not claim to have had personal experience in the case of the elephant. 

 " If this deadly juice is boiled two or three times, the Indians eat it, making 

 soup of it, as a good pottage and tonic; but as it cools, they cease to eat it, 

 for although it will not kill after it has been cooked, they say that it is difficult 

 of digestion if eaten cold. If when the juice is expressed it is boiled dOAvn 

 two-thirds and left to stand two or three days, it turns sweet, and this they 

 use as a sweet beverage, mixing it with other food ; and after it is boiled and 

 settled, the juice turns sour and is used like vinegar or sour wine. * * * 

 When there were many Indians in Hispaniola, if one of them wished to die, 

 he ate the yuca roots, and after two or three days or less he died; but if 

 he drank the fresh juice, he had no time for repentance, for his life ended 

 then and there." Oviedo states that six varieties of yuca, which he names, 

 were grown in Hispaniola. According to the same author, " yuca " was the 

 Haitian name for the plant, and the bread made from it was known as 

 " cagabi." 



9. Manihot dulcis (Gmel.) Pax in Engl. Pflanzenreich IV. 147": 71. 1910. 



Jatropha dulcis Gmel. Onom. Bot. 5: 7, 1772-78. 



Manihot aipi Pohl, Fl. Bras. Icon. Descr. 1: 29. pi. 23. 1827. 



Cultivated in Yucatan, Oaxaca, and perhaps elsewhere; in some localities 

 said to be naturalized. Native of South America. 



Shrub, 1 to 4 meters high; leaves deeply 3 to 13-parted, glabrous or nearly 

 so ; calyx 12 to 14 mm. long ; capsule about 1.5 cm. long. " Yuca dulce " 



* Introduced into Mexico in precolumbian times, and called by the Aztecs 

 '• quauhcamotl," " tree-potato." 



