Succulent plant

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Succulent plants have thickened stems, or leaves, such as this Aloe. Split Aloe.jpg
Succulent plants have thickened stems, or leaves, such as this Aloe .

In botany, succulent plants, also known as succulents, are plants with parts that are thickened, fleshy, and engorged, usually to retain water in arid climates or soil conditions. It is a characteristic that is not used scientifically for the definition of most families and genera of plants because it often can be used as an accurate characteristic only at the single species level. The word succulent comes from the Latin word sucus, meaning 'juice', or 'sap'. [1] Succulent plants may store water in various structures, such as leaves and stems. Some definitions also include roots, thus geophytes that survive unfavorable periods by dying back to underground storage organs may be regarded as succulents. In horticultural use, the term succulent is sometimes used in a way that excludes plants that botanists would regard as succulents, such as cacti. Succulents are often grown as ornamental plants because of their striking and unusual appearance, as well as their ability to thrive with relatively minimal care.

Contents

Many plant families have multiple succulents species found within them (more than 25 plant families). [2] In some families, such as Aizoaceae, Cactaceae, and Crassulaceae, most species are succulents. The habitats of these water-preserving plants are often in areas with high temperatures and low rainfall, such as deserts. Succulents have the ability to thrive on limited water sources, such as mist and dew, which makes them equipped to survive in an ecosystem that contains scarce water sources.

Definition

Center of a succulent (Aloe polyphylla) Succulent in San Francisco.JPG
Center of a succulent ( Aloe polyphylla )

By definition, succulent plants are drought resistant plants in which the leaves, stem, or roots have become more than usually fleshy by the development of water-storing tissue. [3] Other sources exclude roots as in the definition "a plant with thick, fleshy and swollen stems and/or leaves, adapted to dry environments". [4] This difference affects the relationship between succulents and "geophytes" – plants that survive unfavorable seasons as a resting bud on an underground organ. [5] These underground organs, such as bulbs, corms, and tubers, are often fleshy with water-storing tissues. Thus if roots are included in the definition, many geophytes would be classed as succulents. Plants adapted to living in dry environments such as succulents, are termed xerophytes . However, not all xerophytes are succulents, since there are other ways of adapting to a shortage of water, e.g., by developing small leaves which may roll up or having leathery rather than succulent leaves. [6] Nor are all succulents xerophytes, since plants such as Crassula helmsii are both succulent and aquatic. [7]

Some who grow succulents as a hobby may use the term in a different way from botanists. In horticultural use, the term succulent regularly excludes cacti. For example, Jacobsen's three volume Handbook of Succulent Plants does not include cacti. [8] Many books covering the cultivation of these plants include "cacti and succulents" as the title or part of the title. [9] [10] [11] However, in botanical terminology, cacti are succulents, [3] but not the reverse as many succulent plants are not cacti. Cacti bear true spines and appear only in the New World (the Western Hemisphere), and through parallel evolution similar looking plants evolved in completely different plant families in the Old World without spines, a distinct organ structure.

A further difficulty for general identification is that plant families (the genus) are neither succulent nor non-succulent and contain both. In many genera and families there is a continuous gradation from plants with thin leaves and normal stems to those with very clearly thickened and fleshy leaves or stems, so the succulent characteristic becomes meaningless for dividing plants into genera and families. Different sources may classify the same species differently. [12]

Horticulturists often follow commercial conventions and may exclude other groups of plants such as bromeliads, that scientifically, are considered succulents. [13] A practical horticultural definition has become "a succulent plant is any desert plant that a succulent plant collector wishes to grow", without any consideration of scientific classifications. [14] Commercial presentations of "succulent" plants will present those that customers commonly identify as such. Plants offered commercially then as "succulents", will less often include geophytes (in which the swollen storage organ is wholly underground), but will include plants with a caudex, [15] that is a swollen above-ground organ at soil level, formed from a stem, a root, or both. [5]

Appearance

A collection of succulent plants, including cacti, from the Jardin botanique d'Eze, France Eze jardin exotique.JPG
A collection of succulent plants, including cacti, from the Jardin botanique d'Èze, France

The storage of water often gives succulent plants a more swollen or fleshy appearance than other plants, a characteristic known as succulence. In addition to succulence, succulent plants variously have other water-saving features. These may include:

Habitat

Other than Antarctica, succulents can be found within each continent. While it is often thought that most succulents come from dry areas such as steppes, semi-desert, and desert, the world's driest areas do not make for proper succulent habitats. Australia, the world's driest inhabited continent, hosts very few native succulents due to the frequent and prolonged droughts. Even Africa, the continent with the most native succulents, does not host many of the plants in its most dry regions. [17] However, while succulents are unable to grow in these harshest of conditions, they are able to grow in conditions that are uninhabitable by other plants. In fact, many succulents are able to thrive in dry conditions, and some are able to last up to two years without water depending on their surroundings and adaptations. [18] Occasionally, succulents may occur as epiphytes, growing on other plants with limited or no contact with the ground, and being dependent on their ability to store water and gaining nutrients by other means; this niche is seen in Tillandsia . Succulents also occur as inhabitants of sea coasts and dry lakes, which are exposed to high levels of dissolved minerals that are deadly to many other plant species. Potted succulents are able to grow in most indoor environments with minimal care. [19]

Families and genera

Apocynaceae: Pachypodium lealii, stem succulent Bottle-tree.jpg
Apocynaceae: Pachypodium lealii , stem succulent
Asphodelaceae: Haworthia arachnoidea, leaf succulent Haworthia arachnoidea - cobweb aloe.jpg
Asphodelaceae: Haworthia arachnoidea , leaf succulent
Asphodelaceae: Astroloba tenax, leaf succulent Astroloba tenax 6.jpg
Asphodelaceae: Astroloba tenax , leaf succulent
Cactaceae: Rebutia muscula, stem succulent Rebutia muscula.JPG
Cactaceae: Rebutia muscula , stem succulent
Crassulaceae: Crassula ovata, stem and leaf succulent Crassula ovata + Florero.jpg
Crassulaceae: Crassula ovata , stem and leaf succulent
Euphorbiaceae: Euphorbia obesa ssp. symmetrica, stem succulent E obesa symmetrica ies.jpg
Euphorbiaceae: Euphorbia obesa ssp. symmetrica, stem succulent
Cylindropuntia imbricata: stem, woody succulent Treecholla.jpg
Cylindropuntia imbricata : stem, woody succulent
Malvaceae: Adansonia digitata, stem succulent Baobob tree.jpg
Malvaceae: Adansonia digitata , stem succulent
Moringaceae: Moringa ovalifolia, stem succulent Moringa-ovalifolia.jpg
Moringaceae: Moringa ovalifolia , stem succulent
Asparagaceae: Beaucarnea recurvata, stem succulent Pataelefante.jpg
Asparagaceae: Beaucarnea recurvata , stem succulent
Asparagaceae: Dracaena draco, stem succulent Dragon tree 2.jpg
Asparagaceae: Dracaena draco , stem succulent
Euphorbia resinifera Pianta grassa.jpg
Euphorbia resinifera
Succulents kept at 25 degC (77 degF) in a Connecticut greenhouse Succulents in a CT Greenhouse.jpg
Succulents kept at 25 °C (77 °F) in a Connecticut greenhouse
Kalanchoe longiflora Flickr - brewbooks - Kalanchoe longiflora var. coccinea (2).jpg
Kalanchoe longiflora
Echeveria derenbergii Echeveria.derenbergii.7072.jpg
Echeveria derenbergii
Senecio angulatus Senecio angulatus 4.jpg
Senecio angulatus

There are approximately sixty different plant families that contain succulents. [20] Plant orders, families, and genera in which succulent species occur are listed below.

Order Alismatales

Order Apiales

Order Asparagales

Order Asterales

Order Brassicales

Order Caryophyllales

Order Commelinales

Order Cornales

Order Cucurbitales

Order Dioscoreales

Order Ericales

Order Fabales

Order Gentianales

Order Geraniales

Order Lamiales

Order Malpighiales

Order Malvales

Order Myrtales

Order Oxalidales

Order Piperales

Order Poales

Order Ranunculales

Order Rosales

Order Santalales

Order Sapindales

Order Saxifragales

Order Solanales

Order Vitales

Order Zygophyllales

(unplaced order)* Boraginaceae : Heliotropium (unplaced order)* Icacinaceae : Pyrenacantha (geophyte)

There also are some succulent gymnosperms:

Order Pinales

Frenelopsis , Pseudofrenelopsis , Suturovagina , Glenrosa

For some families and subfamilies, most members are succulent; for example the Cactaceae, Agavoideae, Aizoaceae, and Crassulaceae.

The table below shows the number of succulent species found in some families and their native habitat:[ citation needed ]

Family or subfamilySucculent #Modified partsDistribution
Agavoideae 300LeafNorth and Central America
Cactaceae 1600Stem (root, leaf)The Americas
Crassulaceae 1300Leaf (root)Worldwide
Aizoaceae 2000LeafSouthern Africa, Australia
Apocynaceae 500StemAfrica, Arabia, India, Australia
Asphodelaceae 500+LeafAfrica, Madagascar, Australia
Didiereaceae 11StemMadagascar (endemic)
Euphorbiaceae > 1000Stem or leaf or rootAustralia, Africa, Madagascar, Asia, the Americas, Europe
Portulacaceae ~500Leaf and stemThe Americas, Australia, Africa
Cheirolepidiaceae 4, maybe moreLeafWorldwide, except Antarctica
Edgerton Park Conservancy succulent at dusk Edgerton Park Conservancy I.JPG
Edgerton Park Conservancy succulent at dusk

Cultivation

Succulent wall in a nursery in San Francisco, United States consisting of Sempervivum, Echeveria, and Crassula Succulent 'wall'.jpg
Succulent wall in a nursery in San Francisco, United States consisting of Sempervivum , Echeveria , and Crassula

Succulents are favored as houseplants for their attractiveness and ease of care. If properly potted, succulents require little maintenance to survive indoors. [27] Succulents are very adaptable houseplants and will thrive in a range of indoor conditions. [28] For most plant owners, over-watering and associated infections are the main cause of death in succulents. [29]

Succulents can be propagated by different means. The most common is vegetative propagation; this includes cuttings where several inches of stem with leaves are cut and after healing, produce a callus. After a week or so, roots may grow. A second method is division consisting of uprooting an overgrown clump and pulling the stems and roots apart. A third method is propagation by leaf by allowing the formation of a callus. During this method, a bottom leaf is fully removed from the plant often by twisting or cutting. The leaf then dries out and a callus forms preventing the leaf from absorbing too much moisture and thus rotting. This method typically takes up to a few weeks to produce healthy roots that would eventually create new plants. [30] The vegetative propagation can be different according to the species. [31]

See also

Related Research Articles

Cactus Family of mostly succulent plants, adapted to dry environments

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 now 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.

<i>Peperomia</i> Genus of plants

Peperomia is one of the two large genera of the family Piperaceae. Most of them are compact, small perennial epiphytes growing on rotten wood. More than 1500 species have been recorded, occurring in all tropical and subtropical regions of the world, though concentrated in Central America and northern South America. A limited number of species are found in Africa.

<i>Euphorbia</i> A genus of flowering plants in the spurge family Euphorbiaceae

Euphorbia is a very large and diverse genus of flowering plants, commonly called spurge, in the spurge family (Euphorbiaceae). "Euphorbia" is sometimes used in ordinary English to collectively refer to all members of Euphorbiaceae, not just to members of the genus. Some euphorbias are commercially widely available, such as poinsettias at Christmas. Some are commonly cultivated as ornamentals, or collected and highly valued for the aesthetic appearance of their unique floral structures, such as the crown of thorns plant. Euphorbias from the deserts of Southern Africa and Madagascar have evolved physical characteristics and forms similar to cacti of North and South America, so they are often incorrectly referred to as cacti. Some are used as ornamentals in landscaping, because of beautiful or striking overall forms, and drought and heat tolerance.

Crassulaceae A family of flowering plants comprising members popular for horticulture and characterized by a peculiar photosynthetic metabolism adapted to arid conditions

The Crassulaceae, also known as the stonecrop family or the orpine family, are a diverse family of dicotyledon flowering plants characterized by succulent leaves and a unique form of photosynthesis, known as Crassulacean acid metabolism (CAM). Flowers generally have five floral parts. Crassulaceae are usually herbaceous but there are some subshrubs, and relatively few treelike or aquatic plants. Crassulaceae are a medium size monophyletic family in the core eudicots, among the order Saxifragales, whose diversity has made infrafamilial classification very difficult. The family includes approximately 1,400 species and 34–35 genera, depending on the circumscription of the genus Sedum, and distributed over three subfamilies. Members of the Crassulaceae are found worldwide, but mostly in the Northern Hemisphere and southern Africa, typically in dry and/or cold areas where water may be scarce, although a few are aquatic.

Aizoaceae Family of plants

The AizoaceaeMartynov, nom. cons. is a large family of dicotyledonous flowering plants containing 135 genera and about 1800 species. They are commonly known as ice plants or carpet weeds. They are often called vygies in South Africa and New Zealand. Highly succulent species that resemble stones are sometimes called mesembs.

A storage organ is a part of a plant specifically modified for storage of energy (generally in the form of carbohydrates) or water. Storage organs often grow underground, where they are better protected from attack by herbivores. Plants that have an underground storage organ are called geophytes in the Raunkiær plant life-form classification system. Storage organs often, but not always, act as perennating organs which enable plants to survive adverse conditions.

Zamiaceae

The Zamiaceae are a family of cycads that are superficially palm or fern-like. They are divided into two subfamilies with eight genera and about 150 species in the tropical and subtropical regions of Africa, Australia and North and South America.

Proteaceae Family of flowering plants

The Proteaceae are a family of flowering plants predominantly distributed in the Southern Hemisphere. The family comprises 83 genera with about 1,660 known species. Together with the Platanaceae and Nelumbonaceae, they make up the order Proteales. Well-known genera include Protea, Banksia, Embothrium, Grevillea, Hakea and Macadamia. Species such as the New South Wales waratah, king protea, and various species of Banksia, Grevillea, and Leucadendron are popular cut flowers, while the nuts of Macadamia integrifolia are widely grown commercially and consumed. Australia and South Africa have the greatest concentrations of diversity.

Underground stems are modified plants that derive from stem tissue but exist under the soil surface. They function as storage tissues for food and nutrients, propagation of new clones, and perennation. Types include bulbs, corms, rhizomes, stolons, spindle-shaped, and tubers.

<i>Crassula connata</i> species of plant in the family Crassulaceae

Crassula connata is a succulent plant in the family Crassulaceae. It is known by the common names sand pygmyweed and pygmy stonecrop. It is a very small plant which grows in patches on the ground, especially in rocky areas. It is also sometimes associated with vernal pool plant communities. The stems are a few centimeters in length and are covered with tiny fleshy pointed leaves. Each leaf is only millimeters long. The plant is green when new and it matures to shades of pink and red. It is found in western North America and in parts of Central and South America.

A xerophyte is a species of plant that has adaptations to survive in an environment with little liquid water, such as a desert or an ice- or snow-covered region in the Alps or the Arctic. Popular examples of xerophytes are cacti, pineapple and some Gymnosperm plants.

Huntington Desert Garden Calfornian botanical garden for xerophytes

The Huntington Desert Garden is part of The Huntington Library, Art Collections and Botanical Gardens in San Marino, California. The Desert Garden is one of the world's largest and oldest collections of cacti, succulents and other desert plants, collected from throughout the world. It contains plants from extreme environments, many of which were acquired by Henry E. Huntington and William Hertrich in trips taken to several countries in North, Central and South America. One of the Huntington's most botanically important gardens, the Desert Garden brought together a group of plants largely unknown and unappreciated in the beginning of the 1900s. Containing a broad category of xerophytes, the Desert Garden grew to preeminence and remains today among the world's finest, with more than 5,000 species in the 10 acre garden.

<i>Crassula muscosa</i>

Crassula muscosa, synonyms Crassula lycopodioides and Crassula pseudolycopodioides, is a succulent plant native to South Africa and Namibia, belonging to the family of Crassulaceae and to the genus Crassula. It is a houseplant grown worldwide and commonly known as rattail crassula, watch chain, lizard's tail, zipper plant and princess pines.

Crassula marnieriana

Crassula marnierana, common name Jade Necklace or Chinese Pagoda, is a species of succulent in the genus Crassula belonging to the family Crassulaceae.

<i>Orostachys</i> A genus of flowering plants belonging to the stonecrop family (Crassulaceae), comprising succulent species

Orostachys is a genus of the succulent family Crassulaceae that contains about 15 species. It is a biennial herb growing in China, Japan, Kazakhstan, Korea, Mongolia, Russia. Eight species occur in China.

<i>Crassula ovata</i>

Crassula ovata, commonly known as jade plant, lucky plant, money plant or money tree, is a succulent plant with small pink or white flowers that is native to the KwaZulu-Natal and Eastern Cape provinces of South Africa, and Mozambique; it is common as a houseplant worldwide. Much of its popularity stems from the low levels of care needed; the jade plant requires little water and can survive in most indoor conditions. It is sometimes referred to as the money tree; however, Pachira aquatica also has this nickname.

<i>Adromischus cooperi</i> Species of plant

Adromischus cooperi is a species of succulent plant from the family Crassulaceae. The genus name Adromischus comes from ancient Greek adros and mischos, and the species name from James Graham Cooper, an American naturalist and surgeon. The plant is endemic to the Eastern Cape of South Africa.

<i>Kalanchoe longiflora</i>

Kalanchoe longiflora, also known as tugela cliff-kalanchoe or long-flower kalanchoe, is a species of the succulent genus Kalanchoe, in the family Crassulaceae. An obscure shrub native to South Africa, it is known for its multi-coloured foliage and yellow flowers, which bloom in autumn to winter.

<i>Crassula atropurpurea</i>

Crassula atropurpurea is a succulent plant, very common and widespread in the southern Karoo regions of South Africa and Namibia.

<i>Crassula biplanata</i> Species of plant

Crassula biplanata is a succulent plant native to rocky ledges and mountainous areas in the southern parts of South Africa.

References

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  2. Dimmitt, Mark. "The Tucson Cactus and Succulent Society". www.tucsoncactus.org. Retrieved 5 February 2017.
  3. 1 2 Rowley 1980, p. 1
  4. Beentje 2010, p. 116
  5. 1 2 Beentje 2010, p. 32
  6. "xerophyte", Dictionary of Botany, 2001, retrieved 2012-09-23
  7. "Crassula helmsii (aquatic plant, succulent)", Global Invasive Species Database, ISSG, April 15, 2010, retrieved 2012-09-23
  8. Jacobsen 1960
  9. Anderson 1999
  10. Hecht 1994
  11. Hewitt 1993
  12. Rowley 1980, p. 2
  13. Innes & Wall 1995
  14. Martin & Chapman 1977
  15. Martin & Chapman 1977, pp. 19-20
  16. 1 2 3 Compton n.d.
  17. "Succulents in their natural environment".
  18. "Cactuses and Succulents".
  19. "Succulent Care Tips".
  20. "10 Things You Never Knew About Succulents".
  21. "Apiaceae". succulent-plant.com. Retrieved 2018-02-07.
  22. Plants of Southern Africa Retrieved on 2010-1-1
  23. FloraBase - The Western Australian Flora Retrieved on 2010-1-1
  24. Parakeelya. The Plant List.
  25. Dregeochloa pumila. South African National Biodiversity Institute.
  26. "Crassulaceae Genera". Missouri Botanical Garden. Retrieved 2017-10-26.
  27. Kramer, Jack (1977). Cacti and Other Succulents. New York: Abrams. p. 9.
  28. Kramer, Jack (1977). Cacti and Other Succulents. New York: Abrams. p. 49.
  29. SproutingIndoors (2020-06-13). "Succulent Root Rot: What it is and How to Treat it". Sprouting Indoors. Retrieved 2020-06-15.
  30. "Propagating Succulents".
  31. Lee, Debra (2007). Designing with Succulents. Portland, Obregon: Timber Press. p. 133.

Bibliography