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A cactus (pl.: cacti, cactuses, or less commonly, cactus) is a member of the plant family Cactaceae (/ k æ ˈ k t eɪ s i aɪ,-s iː iː /), a family comprising about 127 genera with some 1,750 known species of the order Caryophyllales.
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cactus, (family Cactaceae), flowering plant family (order Caryophyllales) with nearly 2,000 species and 139 genera. Cacti are native through most of the length of North and South America, from British Columbia and Alberta southward; the southernmost limit of their range extends far into Chile and Argentina. Mexico has the greatest number and variet...
Cacti are succulent perennial plants. Cacti generally have thick herbaceous or woody chlorophyll-containing stems. Cacti can be distinguished from other succulent plants by the presence of areoles, small cushionlike structures with trichomes (plant hairs) and, in almost all species, spines or barbed bristles (glochids). Areoles are modified branches, from which flowers, more branches, and leaves (when present) may grow.
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Plants: From Cute to Carnivorous
In most species, leaves are absent, greatly reduced, or modified as spines, minimizing the amount of surface area from which water can be lost, and the stem has taken over the photosynthetic functions of the plant. Only the tropical genera Pereskia and Pereskopsis, both vines, have conventional-looking functional leaves, while the leaves of the Andean Maihuenia are rounded, not flattened. The root systems are generally thin, fibrous, and shallow, ranging widely to absorb superficial moisture.
Cacti vary greatly in size and general appearance, from buttonlike peyote (Lophophora) and low clumps of prickly pear (Opuntia) and hedgehog cactus (Echinocereus) to the upright columns of barrel cacti (Ferocactus and Echinocactus) and the imposing saguaro (Carnegiea gigantea). Most cacti grow in the ground, but several tropical species—including leaf cactus (Epiphyllum), Rhipsalis, and Schlumbergera—are epiphytes, growing on other plants; others live on hard substrates such as rocks, while yet others climb far up trees. Epiphytic species tend to have thin, almost leaflike flattened stems. The appearance of the plant varies also according to whether the stem surface is smooth or ornamented with protruding tubercles, ridges, or grooves.
The primary method of reproduction is by seeds. Flowers, often large and colourful, are usually solitary. All genera have a floral tube, often with many petal-like structures, and other less colourful and almost leaflike structures; the tube grows above a one-chambered ovary. A style topped by many pollen-receptive stigmas also arises from the top of the ovary. The fruit is usually a berry and contains many seeds. Soon after pollination, which may be effected by wind, birds, insects, or bats, the entire floral tube detaches from the top of the ovary to leave a prominent scar.
Cacti are widely cultivated as ornamentals. In addition, various species, notably prickly pears and chollas (Opuntia and Cylindopuntia, respectively), are cultivated as food. In Central and South America, species of Opuntia, Cereus, and others are used as living fences, and wood from columnar cacti is used as fuel in some desert regions. In times o...
Learn about cactus, a flowering plant family with nearly 2,000 species and 139 genera, native to most of North and South America. Find out their physical characteristics, reproduction, uses, and more.
- The Editors of Encyclopaedia Britannica
Feb 22, 2024 · The cactus plant family ( Cactaceae) consists of a number of unique succulent-type plants that thrive in dry conditions. There are thousands of different types of cacti, with all of them being native to the Americas.
- Saguaro Cactus (Carnegiea gigantea) Botanical Name: Carnegiea gigantea. Mature Size: Up to 40 feet tall. Bloom Time: Late spring to early summer. Leaf Color: N/A (Saguaro has modified leaves in the form of spines)
- Barrel Cactus (Ferocactus spp.) Botanical Name: Ferocactus spp. Mature Size: Varies by species, generally small to medium-sized. Bloom Time: Spring to summer.
- Prickly Pear Cactus (Opuntia spp.) Botanical Name: Opuntia spp. Mature Size: Varies by species can range from small to large. Bloom Time: Spring to early summer.
- Christmas Cactus (Schlumbergera spp.) Botanical Name: Schlumbergera spp. Mature Size: Compact, typically around 1-2 feet. Bloom Time: Late fall to early winter.
Oct 19, 2023 · Cactus is native to arid, dry, and drought regions. Coming in a diverse range of shape, size, and color, the jagged spines on the surface of cacti are the modified leaves that change their form to prevent the loss of water. They have a thick and fleshy stem used to retain water.
Learn about over 1,000 types of cactuses with pictures and names, separated by their genera. Find out the features, habitats, and characteristics of each cactus species.
