Top 5 Cactus Plants to Grow for Beginners (Mei 2024)
Cactus, (familie Cactaceae), meervoud cactussen of cactussen, bloeiende plantenfamilie (orde Caryophyllales) met bijna 2.000 soorten en 139 geslachten. Cactussen komen van nature voor in het grootste deel van Noord- en Zuid-Amerika, van Brits-Columbia en Alberta in zuidelijke richting; de meest zuidelijke grens van hun bereik strekt zich uit tot ver in Chili en Argentinië. Mexico heeft de meeste soorten en variëteiten. De enige cactussen die mogelijk inheems zijn in de Oude Wereld, zijn leden van het geslacht Rhipsalis, die voorkomen in Oost-Afrika, Madagaskar en Sri Lanka. Hoewel een paar cactussoorten in tropische of subtropische gebieden wonen, leven de meeste in en zijn ze goed aangepast aan droge gebieden. Zie ook de lijst met planten uit de familie Cactaceae.
Caryophyllales: Cactaceae
De cactussen zijn nieuwsgierige, vaak doornige (stekelige), succulent gesteelde planten die de familie Cactaceae vormen, kenmerkend voor en goed aangepast
Fysieke eigenschappen
Cactussen zijn succulente vaste planten. Cactussen hebben over het algemeen dikke kruidachtige of houtachtige chlorofylhoudende stengels. Cactussen onderscheiden zich van andere vetplanten door de aanwezigheid van areolen, kleine kussenachtige structuren met trichomen (plantenharen) en, bij bijna alle soorten, stekels of haren met weerhaken (glochiden). Areolen zijn gemodificeerde takken, waaruit bloemen, meer takken en bladeren (indien aanwezig) kunnen groeien.
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.
Several cacti develop plantlets at ground level that, as offsets, reproduce the species vegetatively. Many others can reproduce by fragmentation, whereby segments broken from the main plant will readily root to form clonal individuals. Tissues of cacti are broadly compatible so that terminal portions of one species may be grafted on top of another.
The internal structure of cacti stems conforms to the pattern of broad-leaved angiosperms; a cambium layer of dividing cells, located between the woody inner tissues and those near the outside of the stem, is present. The bulk of the stem, however, consists of thin-walled storage cells that contain mucilaginous substances that prevent the loss of moisture. The stem of cacti is the main food-manufacturing and food-storage organ for most species.
Uses
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 of drought, the spines are removed from cacti such as mandacaru (Cereus jamacaru) to use as fodder for livestock. Peyote, from Lophophora williamsii, has been used ceremonially since pre-Columbian times for its hallucinogenic properties, and many cactus species are of local importance in traditional medicine.
