OPUNTIALES CACTI 635 



About 1000 species, chiefly in the regions west of the Missouri river. Many 

 species occur in the arid regions of the southwest. One of the most interesting 

 is the giant cactus (Cereus giganteus} of Arizona, with fluted columns 50 or 

 60 feet high. The common night blooming cereus (C. grandiflorus), with white 

 flowers opening at night, is well known in cultivation. The rjiost commonly 

 cultivated species is C. speciosissimus, with crimson red flowers that open dur- 

 ing the day. The old man cactus (C. senilis) is cultivated because of its long 

 white hanging hairs. Species of the genus Echinocactus, with stem of many 

 ribs, are often cultivated, the most common being . texensis of southern Texas 

 and Arizona and the E. Ottonis of Brazil. A very good quality of leather 

 has been produced from E. Wisliseni and Cereus giganteus. Species of Mamil- 

 laria with tufted stems covered with nipple-shaped tubercles, are often found 

 in cultivation. The Epiphyllum truncatuni, from Brazil, with flattened, leaf- 

 like stems and flowers 2-3 inches long, and the Phyllocactus, native to South 

 America and Mexico, are also cultivated. The large genus Opuntia, of over 

 ISO species, is entirely American. The O. vulgaris, Mill, naturalized in southern 

 Europe, extends from southern New England west and south; O. Rofinesqwi 

 extends from Michigan west; and 0. polyacantha from Wisconsin westward. 

 Several Mexican species are cultivated. The Indian pear or prickly pear (O 

 Ficus-Indica) of the West Indies and South America, produces an edible fruit. 

 Extensively naturalized in North America, South Europe and Asia and as 

 hedge plants. It grows on the lava slopes of Mount Aetna, converting the lava 

 into soil. The cochineal plant (Nopalca coccinellifera} a native of Mexico, is 

 cultivated as the host of the cochineal insect, from which a scarlet carmine 

 dye is obtained. O. Tuna, O. Dillenii and Pereskia also act as hosts of the 

 same insect. The fleshy stem of some Opuntias, after the spines are removed, 

 are used as stock food. The berries of some species like Opuntia Larreyi 

 which belongs to the O. Ficus-Indica group, O. Striptacantha and Echinocereus 

 stratnineus, etc., are eaten. A recent paper by Hare and Griffith described many 

 details of their uses. The Mexicans call them tunas ; an alcoholic drink is also 

 made from the fruit. Some species are used as soil binders in Texas and else- 

 where. 



Injurious properties. The barbed trichomes penetrate the flesh and are diffi- 

 cult to remove. Death of animals has been caused by "hair balls" phyto-bezoars 

 from them being formed in the stomach. Dr. William Trelease, who had occa- 

 sion to examine the "hair balls" produced in some Mexican animal, gives the 

 following account of this phytobezoar : 



"The hair balls were a little over 3]/ 2 inches in diameter and weighed 7 l /> 

 ounces. One ball was probably 4 inches in diameter." It was stated by the phy- 

 sician who sent them to Dr. Trelease that 16 such balls had been taken from the 

 stomach of a bull at the Hacienda de Cruzes; it appears that the chief food of 

 cattle at this time of the year consisted of Opuntias, and that the particular 

 animal in question being allowed to roam at large, sought such food as could 

 be found. These phyto-bezoars were brown in color, "and in appearance some- 

 what suggest felt or rubbed sole leather, and on examination prove to be com- 

 posed, aside from the small nucleus at the center, of the barbed hairs with 

 which the pulvini of the Platopuntias are armed. To the barbs with which these 

 hairs are covered is due their power of felting together, and there is every 

 indication that, starting about some small nucleus of vegetable fiber, they have 

 been compacted into the dense, felty texture by the visceral movements of the 



