4 CACTACEOUS PLANTS. 



The succulent steins and absence of true leaves readily distinguisli 

 the Cacteae from most other families of plants. The Mesembryanthemnm 

 order, however, comes very near in floral characters, but is easily dis- 

 tinguishable by the ovary, which has many cells in the latter, while in the 

 former the ovary has only one cell ; Mesembryanthemums also possess 

 normal leaves. The succulent Euphorbias are recognisable by their 

 irregular flowers and abundant milky, often acrid sap, and the Aloe and 

 Agave family are widely separated in botanical relationship, being- 

 members of the large class of Monocotyledons. A few isolated plants in 

 other families . assume a similar succulent habit, but they cannot be 

 confused with the Cacte£o. 



DISTRIBUTION. 



North and South America are the principal homes of Cactaceous plants, 

 the greatest strength of the order being concentrated in Mexico, whicti 

 contains nearly three-fourths of the entire number known. Brazil, Peru, 

 Chili, Guiana, Colombia, and some other districts in South America also 

 contain representatives, but in relatively small numbers. In Mexico the 

 vegetation assumes an extraordinary appearance owing to the preponder- 

 ance of species of Cereus and other members of the family, where in the 

 several hot, dry, rocky, regions which characterise this portion of the Ame- 

 rican continent, the Cactes flourish together with Agaves, Yuccas, Dasy- 

 lirions, Beaucarneas, Bcheverias, and similar plants of the Serophilous, 

 or heat and drought-loving type. The woodcut (fig. 1) will convey some 

 idea of the aspect of the vegetation in many parts of Mexico ; but one of 

 the most remarkable representations of this scenery is in Julius FroBbel's 

 " Travels in Central America and Mexico," pourtraying the lower part of 

 the valley of Santa Cruz, in which are shown over fifty " Saguarro trees," 

 as the Cereus giganteus is termed, some very strangely branched near tL& 

 summit, and attaining the height of from 30 to 50 feet. In the Eocky 

 Mouatains some members of the family are found at great elevations, 

 several having been observed by Mr. E. G. Loder exposed to very low 

 temperatures, and are practically hardy in this country, forming a 

 group of additional interest to the cultivator. 



I-IISTORY. 



The Cactaoex, or CaelcEe as this family is termed by some writers, 

 derives its name from the v;orA Cactus, under "nhich generic title 

 Linnffius grouped all the forms that were known in his time, and the 

 name is still popularly applied to jilants possessing the general characters 



