STANDLEY TREES AND SHRUBS OF MEXICO. 863 



Areoles with 2 to 12 spines ; joints green. 



Joints narrow, 4 to 7 times as long as wide 4. N. dejecta. 



Joints oblong or oblong-obovate, 2 to 4 times as long as wide. 



Spines 2 to 4 ; joints not tuberculate 5. N. karwinskiana. 



Spines 4 to 12 ; joints strongly tuberculate 6. N. inaperta. 



1. Nopalea cochenillifera (L.) Salm-Dyck, Cact. Hort. Dyck. 1849. 64. 1850. 

 Cactus cochenillifer L. Sp PI. 468. 1753. 



Opuntia cochineUfera Mill. Gard. Diet. ed. 8. Opuntia No. 6. 1768. 



Cultivated throughout tropical America. 



Often tall plants, 3 to 4 meters high, with trunks up to 20 cm. thick ; branches 

 of ascending or spreading oblong joints, sometimes 50 cm. long, green, bright 

 green at first ; spines none or rarely minute ones developing on the older joints ; 

 glochids numerous, caducous ; flowers appearing from the tops of the joints, 

 usually in great abundance; flower, from base of ovary to tip of style, 5.5 cm. 

 long; ovary nearly globular, 2 cm. long, with low diamond-shaped tubercles, its 

 areoles bearing many glochids ; sepals broadly ovate, acute, scarlet; petals a 

 little longer than the sepals, otherwise similar, persistent; stamens pinkish, 

 exserted 1 to 1.5 cm. beyond the petals ; stigma lobes 6 or 7. exserted beyond 

 the stamens ; style swollen just above its base into a broad disk ; fruit red, about 

 5 cm. long ; seeds about 5 mm. long and 3 mm. wide. " Nocheznopalli " 

 (Nahuatl) ; "nopal de San Gabriel" (Oaxaca) ; "tuna mansa " (Porto Rico) ; 

 "tuna," "nopal" (El Salvador). 



Nopalea cochenillifera is one of the best known of Mexican plants, particu- 

 larly because of the fact, as indicated by the specific name, that it was upon 

 this cactus that there were propagated the cochineal insects from which was ob- 

 tained the famous dye of the same name. The source of the dye was well 

 known to the precolumbian inhabitants of Mexico, who used it for coloring va- 

 rious articles. Immediately after the Conquest the export of cochineal was 

 begun, and it was long one of the chief articles of tribute to the crown. The 

 industry was later established in Spain, India, Jamaica, the Canary Islands, and 

 elsewhere. The principal producer of the dye was probably the Canaries, and 

 from those islands in 1868 more than 6,000,000 pounds, valued at $4,000,000 

 v-as exported. With the development of coal-tar dyes this industry quickly de- 

 cayed. 



The cochineal insects were " planted " upon the branches of the plants, where 

 they quickly multiplied, and were later brushed off into bags. After hav- 

 ing been dried, they became the cochineal of commerce. Large plantations of 

 Nopalea plants were made in Mexico for this purpose, the chief centers of 

 production being in Guerrero and Oaxaca. It should be noted that the 

 cochineal insect lives upon Opuntias, and extends as far north as the State 

 of Colorado. 



The fruit is edible. The joints are sometimes applied as poultices to relieve 

 articular rheumatism, erysipelas, ophthalmia, earache, and toothache. 



2. Nopalea gaumeri Britt. «& Rose, Cactaceae 1: 216. 1919. 

 Yucahin ; tj-pe locality, near Silam. 



About 3 meters high, much branched ; joints small, linear-oblong or oblong- 

 oblanceolate, 6 to 12 cm. long, 2 to 3 cm. broad, rather thin ; areoles small, 1 to 2 

 cm. apart; spines very unequal, 5 to 20 mm. long, acicular, 4 to 12, yellowish 

 when young ; flower small, including ovary and stamens about 4 cm. long ; sepals 

 -ovate, acute; petals oblong, 12 mm. long; stamens long-exserted ; style longer 

 than the stamens ; fruit red, darker within, obovoid, 3 cm. long, its numerous 

 areoles bearing spines and yellow glochids ; umbilicus prominent, 1 cm. deep ; 

 seeds about 4 mm. broad, with very narrow margin and very thin testa. 



