Cactaceae, Euphorbiaceae), of parasites, and of saprophytes.
The western dry areas have the old-world leguminous Astragalus and Prosopis (Mesquit), but are especially characterized by the northward extension of the new-world tropical Cactaceae, Mgmmillaria, Cereus and Opuntia, by succulent Amar llideae such as A gave (of which the so-called American aloe is a type), and by arborescent Liliaceae (Yucca).
Cactaceae are widely spread and both northwards and southwards extend into temperate regions.
The nearly related Ficoideae replace the new-world Cactaceae, but the habit of the latter is simulated by fleshy Euphorbias and Asclepiads, just as that of A gave is by the liliaceous Aloe.
A few Cactaceae extend to Chile.
As applied by Linnaeus, the name Cactus is almost conterminous with what is now regarded as the natural order Cactaceae, which embraces several modern genera.
Cactaceae belong almost entirely to the New World; but some of the Opuntias have been so long distributed over certain parts of Europe, especially on the shores of the Mediterranean and the volcanic soil of Italy, that they appear in some places to have taken possession of the soil, and to be distinguished with difficulty from the aboriginal vegetation.
Species of Cactaceae), or the style bends so that the stigma is brought within the range of the pollen (e.g.
The similarity of certain xerophilous Euphorbiaceae to Cactaceae is a ready illustration of this phenomenon.
It consists of the females of Coccus cacti, an insect of the family Coccidae of the order Hemiptera, which feeds upon various species of the Cactaceae, more especially the nopal plant, Opuntia coccinellifera, a native of Mexico and Peru.