CACTACE^ OF MEXICO — SAFFORD. 



549 



food for cattle in arid regions. The rigid, sharp spines Avith which 

 most species are armed (pi. 10, fig. 6) is a serious drawback in feeding 

 them to cattle, but these are frequently removed by singeing the pads 

 with a torch. Efforts have been made to propagate spineless forms, 

 and these have in many cases been successful.'^ 



3. Nopalea. — This genus is closel}^ allied to Opuntia, but it may 

 easily be distinguished by its flowers, the perianth of which is erect 

 instead of widely spreading, and the stamens are longer than the 

 petals, though they are exceeded by the style. The most important 

 species of this genus is Nopalea coccineUifera, the " nocheznopalli " on 

 which the cochineal insect is reared. The flower is of a beautiful rose 

 color or crimson. The fruit is edible, but is inferior to most of the 

 Opuinta fruits sold in the 

 Mexican markets. The 

 plants are usually more 

 or less tree like, growing 

 to a height of 3 or 4 me- 

 ters, with the trunk and 

 older branches cylindrical 

 or nearly so. The younger 

 parts are flat and green, 

 the joints oblong or ovate 

 and compressed, usually 

 spineless when young, and 

 bearing small, fleshy ca- 

 ducous leaves like those 

 of Opuntia, but sometimes 

 becoming spiny when 

 older. This plant was 

 extensively cultivated by 

 the Mexicans before the discover}- of America, for the sake of the 

 dj^e-yielding insect which feeds upon it. Its cultivation was after- 

 wards introduced into Guatemala, Honduras, the Canary Islands, 

 Algeria, Java, and Australia. In recent years cochineal has largely 

 been supplanted by aniline dj-es, and its cultivation has been dis- 

 continued in nearly every place but the Canary Islands. The prin- 

 cipal sources of its supply were formerly the states of Guerrero and 

 Oaxaca. Other species of the genus growing in Mexico are Nopalea 

 dejecta (called nopal chamacuero, at Victoria, Tamaulipas), which 

 has narrowly oblong joints armed with whitish spines, and N. har- 

 winskiana^ which grows in the vicinity of Colima, on the Pacific 

 coast. It is probably this species which grows about Guadalajara, 



Fig. 13. — Opuntia flower, 

 vertical section. 



Fig. 14. — Nopalea 

 flower. 



° See Griffiths, David. Tlie Prickly Pear as a farm crop. 

 Bur. Pluiit Industry Bull. 124. 1908. 



U. S. Dept. Agr., 



