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Кактусовые (Cactaceae) 6/21/08—12/25/19

A cactus is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word "cactus" derives, through Latin, from the Ancient Greek κάκτος, kaktos, a name originally used by Theophrastus for a spiny plant whose identity is not certain. Cacti occur in a wide range of shapes and sizes. Most cacti live in habitats subject to at least some drought. Many live in extremely dry environments, even being found in the Atacama Desert, one of the driest places on earth. Cacti show many adaptations to conserve water. Almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water. Unlike many other succulents, the stem is the only part of most cacti where this vital process takes place. Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves. As well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade. In the absence of leaves, enlarged stems carry out photosynthesis. Cacti are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north—except for Rhipsalis baccifera, which also grows in Africa and Sri Lanka.

Cactus spines are produced from specialized structures called areoles, a kind of highly reduced branch. Areoles are an identifying feature of cacti. As well as spines, areoles give rise to flowers, which are usually tubular and multipetaled. Many cacti have short growing seasons and long dormancies, and are able to react quickly to any rainfall, helped by an extensive but relatively shallow root system that quickly absorbs any water reaching the ground surface. Cactus stems are often ribbed or fluted, which allows them to expand and contract easily for quick water absorption after rain, followed by long drought periods. Like other succulent plants, most cacti employ a special mechanism called "crassulacean acid metabolism" (CAM) as part of photosynthesis. Transpiration, during which carbon dioxide enters the plant and water escapes, does not take place during the day at the same time as photosynthesis, but instead occurs at night. The plant stores the carbon dioxide it takes in as malic acid, retaining it until daylight returns, and only then using it in photosynthesis. Because transpiration takes place during the cooler, more humid night hours, water loss is significantly reduced.

Many smaller cacti have globe-shaped stems, combining the highest possible volume for water storage, with the lowest possible surface area for water loss from transpiration. The tallest free-standing cactus is Pachycereus pringlei, with a maximum recorded height of 19.2 m (63 ft), and the smallest is Blossfeldia liliputiana, only about 1 cm (0.4 in) in diameter at maturity. A fully grown saguaro (Carnegiea gigantea) is said to be able to absorb as much as 200 U.S. gallons (760 l; 170 imp gal) of water during a rainstorm. A few species differ significantly in appearance from most of the family. At least superficially, plants of the genus Pereskia resemble other trees and shrubs growing around them. They have persistent leaves, and when older, bark-covered stems. Their areoles identify them as cacti, and in spite of their appearance, they, too, have many adaptations for water conservation. Pereskia is considered close to the ancestral species from which all cacti evolved. In tropical regions, other cacti grow as forest climbers and epiphytes (plants that grow on trees). Their stems are typically flattened, almost leaf-like in appearance, with fewer or even no spines, such as the well-known Christmas cactus or Thanksgiving cactus (in the genus Schlumbergera).



Cacti have a variety of uses: many species are used as ornamental plants, others are grown for fodder or forage, and others for food (particularly their fruit). Cochineal is the product of an insect that lives on some cacti.



Many succulent plants in both the Old and New World, such as some Euphorbiaceae (euphorbias), bear a striking resemblance to cacti, and may incorrectly be called "cactus" in common usage.
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Астроцилиндроопунция шиловидная (Austrocylindropuntia subulata)

Астроцилиндроопунция шиловидная (Austrocylindropuntia subulata)

2 images

Бразилиопунция бразильская (Brasiliopuntia brasiliensis)

Бразилиопунция бразильская (Brasiliopuntia brasiliensis)

5 images

Гилоцереус волнистый 'Мачо из Милана' (Hylocereus undatus 'Macho Milano')

Гилоцереус волнистый 'Мачо из Милана' (Hylocereus undatus 'Macho Milano')

1 image

Гилоцереус волнистый, извилистый (Hylocereus undatus)

Гилоцереус волнистый, извилистый (Hylocereus undatus)

5 images

Гимнокалициум Бальда (Gymnocalycium baldianum)

Гимнокалициум Бальда (Gymnocalycium baldianum)

28 images

Гимнокалициум Хорста (Gymnocalycium horstii)

Гимнокалициум Хорста (Gymnocalycium horstii)

2 images

Кактус 3 (Cactaceae sp.)

Кактус 3 (Cactaceae sp.)

4 images

Кактус 4 (Cactaceae sp.)

Кактус 4 (Cactaceae sp.)

3 images

Кактус 6 (Cactaceae sp.)

Кактус 6 (Cactaceae sp.)

6 images

Кактус 7 (Cactaceae sp.)

Кактус 7 (Cactaceae sp.)

2 images

Кактус 10 (Cactaceae sp.)

Кактус 10 (Cactaceae sp.)

3 images

Кактус 11 (Cactaceae sp.)

Кактус 11 (Cactaceae sp.)

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Кактус 12 (Cactaceae sp.)

Кактус 12 (Cactaceae sp.)

2 images

Кактус 13 (Cactaceae sp.)

Кактус 13 (Cactaceae sp.)

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Кактус 14 (Cactaceae sp.)

Кактус 14 (Cactaceae sp.)

5 images

Кактус 15 (Cactaceae sp.)

Кактус 15 (Cactaceae sp.)

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Кактус 16 (Cactaceae sp.)

Кактус 16 (Cactaceae sp.)

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Карнегия гигантская, Сагуаро (Carnegiea gigantea)

Карнегия гигантская, Сагуаро (Carnegiea gigantea)

4 images

Клейстокактус волчий-хвост (Cleistocactus vulpis-cauda)

Клейстокактус волчий-хвост (Cleistocactus vulpis-cauda)

3 images

Клейстокактус канделильский (Cleistocactus candelilla)

Клейстокактус канделильский (Cleistocactus candelilla)

7 images

Клейстокактус самайпатанский (Cleistocactus samaipatanus)

Клейстокактус самайпатанский (Cleistocactus samaipatanus)

4 images

Клейстокактус Штрауса (Cleistocactus strausii)

Клейстокактус Штрауса (Cleistocactus strausii)

3 images

Маммилария центроколючковая (Mammillaria centricirrha)

Маммилария центроколючковая (Mammillaria centricirrha)

6 images

Маммиллярия бомбицина (Mammillaria bombycina)

Маммиллярия бомбицина (Mammillaria bombycina)

3 images

Маммиллярия великолепная (Mammillaria magnifica)

14 images

Маммиллярия Гейдера (Mammillaria heyderi)

3 images

Маммиллярия деципиенс 'Птичье гнездо' (Mammillaria decipiens 'Bird nest')

2 images

Маммиллярия Карвинского (Mammillaria karwinskiana)

3 images

Маммиллярия матудая (Mammillaria matudae)

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Маммиллярия спиноссима (Mammillaria spinosissima)

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Маммиллярия удлиненная 'Узелок' (Mammillaria elongata 'Crest')

2 images

Маммилярия удлинненая (Mammillaria elongata)

6 images

Опунция беловолосая (Opuntia leucotricha)

10 images

Опунция индийская (Opuntia ficus-indica)

4 images

Опунция микроволосистая (Opuntia microdasys)

6 images

Опунция робуста (Opuntia robusta)

12 images

Ребутия мускула (Rebutia muscula)

10 images

Селеницереус крупноцветковый (Selenicereus grandiflorus)

3 images

Цереус Хилдмаиана подвид. уругвайский 'Ужасающий' (Cereus hildmannianus subsp. uruguayanus 'Monstrosus')

7 images

Цефалоцереус старческий (Cephalocereus senilis)

3 images

Цилиндропунция колючейшая (Cylindropuntia spinosior)

4 images

Цилиндропунция чехольчатая (Cylindropuntia tunicata)

10 images

Шлюмбергера Бакли (Schlumbergera х buckleyi (Schlumbergera truncata x Schlumbergera russelliana))

7 images

Эпифиллум x гибридный (Epiphyllum x hybrida)

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Эхинокактус Грусона (Echinocactus grusonii)

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Эхинопсис дикообразный (Echinopsis hystrichoides)

4 images

Эхинопсис острограанный (Echinopsis oxygona)

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Эхинопсис хамецереус (Echinopsis chamaecereus)

11 images

Эхиноцереус Виерики (Echinocereus viereckii)

2 images

Эхиноцереус пепельно-серый (Echinocereus cinerascens)

3 images

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