The entire valley of the Rio Grande, from El Paso to Brownsville, grows many species of cactus, and other prickly coriaceous shrubs.
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.
Pilocereus, the old man cactus, forms a small genus with tallish erect, fleshy, angulate stems, on which, with the tufts of spines, are developed hair-like bodies, which, though rather coarse, bear some resemblance to the hoary locks of an old man.
The variation is from dwarf mountain pine to giant cactus and dates.
There are broad plains covered with salt and alkali, and others supporting only scattered bunch grass, sage bush, cactus and other arid land plants.
The general elevation is low, the surface sandy and covered with cactus and mesquite growth, and hot, semi-arid conditions prevail.
Opuntia, the prickly pear, or Indian fig cactus, is a large typical group, comprising some 150 species, found in North America, the West Indies, and warmer parts of South America, extending as far as Chile.
An important product of the plateau and of the open districts of the tierras calientes, growing in the most arid places, is the " nopal " or prickly pear cactus (Opuntia ficus indica).
New Mexico has such a great range of elevations that all four of the zones of vegetation into which the South-West has been divided according to altitude are found within its limits; namely, the zone of cactus, yucca and agave (3000-3500 ft.), where grass is scanty; the zone of greasewood and sage-brush (3500-4900 ft.), where there is little grass, and the cactus species are less numerous; the zone of the cedar (4900-6800 ft.); and the zone of the pine and fir (6800 - 10,800 ft.), in which grass is more abundant.
The cochineal insect is found on the cactus which grows in abundance in the vicinity, and the town is known throughout Ecuador for its manufacture of boots and shoes, and for a cordage made from cabuya, the fibre of the agave plant.
Near the Cordillera and on its lower slopes a tall branched cactus is met with, and there are Salicornias and Salsolas near the coast.
Poplars grow in the valleys, and the cactus and sage brush are common.
There is but little natural vegetation to be seen - ragged yucca trees, many species of agave and cactus, scrubby mesquite bushes, sage bushes and occasional clumps of coarse grasses.
This struggle for existence has completely changed the habits of some plants, turning the palm and the cactus into climbers, and even some normal species into epiphytes.
Here grow, among the introduced plants, the coffee tree, the date-palm, the sugar-cane, the banana, the orange tree, the American agave and two species of cactus; and among indigenous plants, the dragon tree on the north-west of Teneriffe.
They include the rugged bare mass of Gerizim (2849 ft.), the smoother cactus-clad cone of Ebal (3077), and farther south Tell `Asur (3318) at which point begins the Judaean range.
In places the giant cactus grows in groves, attaining a height of 40 and even 50 ft.
This terminates in a long spike thickly studded with white blossoms. The grass-tree gives as distinct a character to an Australian picture as the agave and cactus do to the Mexican landscape.
Its flat-roofed Moorish houses are enclosed by gardens of cactus, dwarf palm, orange and other subtropical plants, interspersed with masses of rock.
The kekop tree, the orange, the laurel, the juniper, the wild cactus, the curry plant, wild sage and celery flourish.
But the strip of coast between the Apennines and the sea, known as the Riviera of Genoa, is not only extremely favourable to the growth of olives, but produces oranges and lemons in abundance, while even the aloe, the cactus and the palm flourish in many places.
At first sight a South African Euphorbia might be mistaken for a South American Cactus, an Aloe for an A gave, a Senecio for ivy, or a New Zealand Veronica for a European Salicornia.
There is but one cactus indigenous to Natal; it is found hanging from perpendicular rocks in the midlands.
There are also many fruits found growing wild, like those of the cactus and various palms, and these are largely consumed.
- This genus, which comprises nearly 300 species, mostly Mexican, with a few Brazilian and West Indian, is called nipple cactus, and consists of globular or cylindrical succulent plants, whose surface instead of being cut up into ridges with alternate furrows, as in Melocactus, is broken up into teat-like cylindrical or angular tubercles, spirally arranged, and terminating in a radiating tuft of spines which spring from a little woolly cushion.
Peireskia Aculeata, or Barbadoes gooseberry, the Cactus peireskia of Linnaeus, differs from the rest in having woody stems and leaf-bearing branches, the leaves being somewhat fleshy, but otherwise of the ordinary laminate character.
Conolophus subcristatus and Amblyrhynchus cristatus inhabit the Galapagos; the former feeds upon cactus and leaves, the latter is semi-marine, diving for the algae which grow below tide-marks.
Then, there are the mangrove-fringed coasts and the dripping wooded slopes where rare orchids thrive, and above these, on the inland side of the sierra, a treeless, sun-scorched table-land where only the cactus, yucca, and other coarse vegetation of the desert can thrive without irrigation.
As one of the Aztec chiefs at the time of the founding of their city was called Tenoch, it is likely that from him was derived the name Tenochtitlan or " Stone-cactus place."
The simplest forms of these depict the objects signified by the name, as where Chapultepec or " grasshopper-hill " is represented by a grasshopper on a hill, or a stone with a cactus on it stands for Tenoch or " stonecactus," the founder of Tenochtitlan.
Some of its characteristic mammals and birds are the long-eared desert fox, four-toed kangaroo rats, Sonoran pocket mice, big-eared and tiny white-haired bats, road runner, cactus wren, canyon wren, desert thrashers, hooded oriole, black-throated desert sparrow, Texas night-hawk and Gambels quail.
The cactus, sagebrush and yucca, types characteristic of more arid regions, are found.
Among plants remarkable in their appearance and structure may be noted the cactus-like Euphorbiae or spurge plants, the Stapelia or carrion flower, and the elephant's foot or Hottentots' bread, a plant of the same order as the yam.
The following is a select list of genera of stove plants (climbers are denoted by *, bulbous and tuberous plants by f) Acalypha Achimenest Aeschynanthus Allamanda* Alocasiat Amaryllist Anthurium Aphelandra Aralia Ardisia Arisaemaf Aristolochia * Ataccia Begonia Bertolonia Bignonia* Bromeliads Cactus Caladium f Calathea Centropogon Cissus* Clerodendron * Crinumt Codiaeum (Croton) ORcftIDs.
Here the more common European plants and trees give place to the wild olive, the caper bush, the aloe, the cactus, the evergreen oak, the orange, the lemon, the palm and other productions of a tropical climate.