Succulent plants, also known as succulents or fat plants, are water-retaining plants adapted to xerophilic climatic or soil conditions. Succulent plants store water in their leaves, stems and/or roots. The storage of water often gives succulent plants a more swollen or fleshy appearance than other plants, also known as succulence. In addition to succulence, succulent plants variously have other water-saving features. These may include:
- CAM metabolism to minimise water loss
- Absent, reduced, or cylindrical to spherical leaves
- reduction in the number of stomata
- stems, rather than leaves, as the main site of photosynthesis
- a compact, reduced, cushion-like, columnar or spherical growth form
- ribs enabling rapid increases in plant volume and decreasing surface area exposed to the sun
- waxy, hairy or spiny outer surface to reduce water loss via the creation of a humid microhabitat around the plant and a reduction in air movement near the surface of the plant.
Many succulents come from the dry areas of the tropics and subtropics, such as steppes, semi-desert and desert. High temperatures and low precipitation force plants to collect and store water in order to survive long dry periods. Succulents also occur as epiphytes, as such they have limited or no contact with the ground, and are dependent on their ability to store water. Succulents also occur as inhabitants of sea coasts, or salt pans which are exposed to high levels of dissolved minerals.
The best known succulents are cacti (family: Cactaceae). Virtually all cacti are succulents, but many succulents are not cacti.
Families and genera
Plant families and genera in which succulent species occur are listed below.
- Agavaceae: Agave, Beschorneria, Chlorophytum, Furcraea, Hesperaloe, Hesperoyucca, Yucca
- Aizoaceae: Acrodon, Aloinopsis, Amoebophyllum, Amphibolia, Antegibbaeum, Apatesia, Aptenia, Arenifera, Argyroderma, Aridaria, Astridia, Bergeranthus, Berrisfordia, Braunsia, Brownanthus, Calamophyllum, Carpobrotus, Carruanthus, Caryotophora, Cephalophyllum, Cerochlamys, Chasmatophyllum, Cheiridopsis, Conicosia, Conophytum, Cylindrophyllum, Dactylopsis, Delosperma, Dicrocaulon, Dinteranthus, Dorotheanthus, Dracophilus, Drosanthemum, Eberlanzia, Ebracteola, Ectotropis, Enarganthe, Erepsia, Esterhuysenia, Eurystigma, Faucaria, Fenestraria, Frithia, Gibbaeum, Glottiphyllum, [[H
alenbergia]], Hereroa, Herrea, Herreanthus, Hydrodea, Hymenogyne, Imitaria, Jacobsenia, Juttadinteria, Kensitia, Khadia, Lampranthus, Lapidaria, Leipoldtia, Lithops, Machairophyllum, Malephora, Maughaniella, Mesembryanthemum, Mestoklama, Meyerophytum, Micropterum, Mimetophytum, Mitrophyllum, Monilaria, Muiria, Namaquanthus, Namibia, Nanathus, Nelia, Neohenricia, Neorhine, Nycteranthus, Octopoma, Odontophorus, Oophytum, Ophthalmophyllum, Orthopterum, Oscularia, Ottosonderia, Pherelobus, Platythyra, Pleiospilos, Polymita, Prenia, Psammophora, Psicaulon, Rabiea, Rhinephyllum, Rhombophyllum, Ruschia, Ruschianthemum, Ruschianthus, Saphesia, Sceletium, Schwantesia, Scopologena, Semnanthe, Skiatophytum, Smicrostigma, Sphalmanthus, Stayneria, Stomatium, Synaptophyllum, Titanopsis, Trichodiadema, Vanheerea, Vanzijlia, Wooleya, Zeuktophyllum
- Amaranthaceae: Arthraerva, Salicornia
- Amaryllidaceae: Boophane, Brunsvigia, Cyrtanthus, Haemanthus, Rauhia
- Anacardiaceae: Operculicaria, Pachycormus
- Apiaceae: Steganotaenia
- Apocynaceae: Adenium, Mandevilla, Pachypodium, Plumeria
- subfamily Asclepiadoideae (syn. Asclepiadaceae): Absolmsia, Asclepias, Aspidoglossum, Aspidonepsis, Baynesia, Brachystelma, Caralluma, Ceropegia, Cibirhiza, Cynanchum, Dischidia, Dischidiopsis, Duvalia, Duvaliandra, Echidnopsis, Edithcolea, Fanninia, Fockea, Glossostelma, Hoodia, Hoya, Huernia, Huerniopsis, Ischnolepis, Larryleachia, Lavrania, Madangia, Marsdenia, Matelea, Micholitzia, Miraglossum, Notechidnopsis, Odontostelma, Ophionella, Orbea, Orbeanthus, Pachycarpus, Pectinaria, Petopentia, Piaranthus, Pseudolithos, Quaqua, Raphionacme, Rhytidocaulon, Riocreuxia, Sarcorrhiza, Sarcostemma, Schizoglossum, Schlechterella, Stapelia, Stapelianthus, Stapeliopsis, Stathmostelma, Stenostelma, Stomatostemma, Tavaresia, Trachycalymma, Tridentea, Tromotriche, White-sloanea, Xysmalobium
- Araceae: Zamioculcas
- Araliaceae: Cussonia
- Asparagaceae: Myrsiphyllum
- Asphodelaceae: Aloe, Astroloba, Bulbine, Chortolirion, Gasteria, Haworthia, Poellnitzia, Trachyandra
- Asteraceae: Baeriopsis, Coulterella, Crassocephalum, Didelta, Gynura, Osteospermum, Othonna, Polyachyrus, Pteronia, Senecio
- Balsaminaceae: Impatiens
- Basellaceae: Anredera, Basella
- Begoniaceae: Begonia
- Bombaceae: Adansonia, Cavanillesia, Ceiba, Pseudobombax
- Brassicaceae: Heliophila, Lepidium
- Bromeliaceae: Abromeitiella
- Burseraceae: Beiselia, Bursea, Commiphora
- Cactaceae:
Acanthocalycium, Acanthocereus, Ariocarpus, Armatocereus, Arrojadoa, Arthrocereus, Astrophytum, Austrocactus, Aztekium, Bergerocactus, Blossfeldia, Brachycereus, Browningia, Brasilicereus, Calymmanthium, Carnegiea, Cephalocereus, Cephalocleistocactus, Cereus, Cintia, Cipocereus, Cleistocactus, Coleocephalocereus, Copiapoa, Corryocactus, Coryphantha, Dendrocereus, Denmoza, Discocactus, Disocactus, Echinocactus, Echinocereus, Echinopsis, Epiphyllum, Epithelantha, Eriosyce, Escobaria, Escontria, Espostoa, Espostoopsis, Eulychnia, Facheiroa, Ferocactus, Frailea, Geohintonia, Gymnocalycium, Haageocereus, Harrisia, Hatiora, Hylocereus, Jasminocereus, Lasiocereus, Leocereus, Lepismium, Leptocereus, Leuchtenbergia, Lophophora, Maihuenia, Malacocarpus, Mammillaria, Mammilloydia, Matucana, Melocactus, Micranthocereus, Mila, Monvillea, Myrtillocactus, Neobuxbaumia, Neolloydia, Neoraimondia, Neowerdermannia, Obregonia, Opuntia, Oreocereus, Oroya, Ortegocactus, Pachycereus, Parodia, Pediocactus, Pelecyphora, Peniocereus, Pereskia, Pereskiopsis, Pilosocereus, Polaskia, Praecereus, Pseudoacanthocereus, Pseudorhipsalis, Pterocactus, Pygmaeocereus, Quiabentia, Rauhocereus, Rebutia, Rhipsalis, Samaipaticereus, Schlumbergera, Sclerocactus, Selenicereus, Stenocactus, Stenocereus, Stephanocereus, Stetsonia, Strombocactus, Tacinga, Thelocactus, Turbinicarpus, Uebelmannia, Weberbauerocereus, Weberocereus, Yungasocereus
- Campanulaceae: Brighamia
- Capparidaceae: Maerua
- Caricaceae: Carica, Jacarathia
- Chenopodiaceae
- Cochlospermaceae
- Commelinaceae: Aneilema, Callisia, Cyanotis, Tradescantia, Tripogandra
- Convolvulaceae: Ipomea, Sictocardia, Turbina
- Crassulaceae: Adromischus, Aeonium, Afrovivella, Aichryson, Cotyledon, Crassula, Cremnophila, Cremnosedum, Dudleya, Echeveria, Graptopetalum, Hylotelephium, Hypagophytum, Kalanchoe, Lenophyllum, Meterostachys, Monanthes, Orostachys, Pachyphytum, Perrierosedum, Phedimus, Pistorinia, Prometheum, Pseudosedum, Rhodiola, Rosularia, Sedella, Sedum, Sempervivum, Sinocrassula, Thompsonella, Tylecodon, Umbilicus, Villadia
- Cucurbitaceae: Apodanthera, Brandegea, Cephalopentandra, Ceratosanthes, Citrullus, Coccinia, Corallocarpus, Cucumella, Cucumis, Cucurbita, Cyclantheropsis, Dendrosicyos, Doyera, Eureindra, Fevillea, Gerrandanthus, Gynostemma, Halosicyos, Ibervilla, Kedostris, Marah, Momordica, Neoalsomitra, Odosicyos, Parasicyos, Syrigia, Telfairia, Trochomeria, Trochomeriopsis, Tumamoca, Xerosicyos, Zehneria, Zygosicyos
- Didiereaceae: Alluaudia, Alluaudiopsis, Decaria, Didierea
- Dioscoreaceae: Dioscorea
- Doryanthaceae: Doryanthes
- Ericaceae: Sphyrospermum
- Eriospermaceae: Eriospermum
- Euphorbiaceae: Cnidoscolus, Euphorbia, Jatropha
- Fabaceae: Delonix, Dolichos, Erythrina, Neorautanenia, Pachyrhizus, Tylosema
- Fouquieriaceae: Fouquieria
- Geraniaceae: Monsonia, Pelargonium
- Gesneriaceae: Aeschynanthus, Alsobia, Chirita, Codonanthe, Columnea, Nematanthus, Sinningia, Streptocarpus
- Hyacinthaceae: Albuca, Bowiea, Dipcadi, Drimia, Hyacinthus, Lachenalia, Ledebouria, Litanthus, Massonia, Ornithogalum, Rhadamanthus, Rhodocodon, Schizobasis, Urginea, Whiteheadia
- Icacinaceae: Pyrenacantha
- Lamiaceae: Aeollanthus, Dauphinea, Perrierastrum, Plectranthus, Solenostemon, Tetradenia, Thorncroftia
- Lentibulariaceae
- Loasaceae: Schismocarpus
- Loranthaceae: Tapinanthus
- Melastomataceae: Medinilla
- Meliaceae: Entandrophragma
- Menispermaceae: Chasmanthera, Stephania, Tinospora
- Moraceae: Dorstenia, Ficus
- Moringaceae: Moringa
- Nolanaceae: Nolana
- Nolinaceae: Beaucarnea, Calibanus, Dasylirion, Nolina
- Orchidaceae subfamily Epidendroideae Phalaenopsis
- Oxalidaceae: Oxalis
- Passifloraceae: Adenia
- Pedaliaceae: Pterodiscus, Sesamothamnus, Uncarina
- Phyllanthaceae: Phyllanthus
- Phytolaccaceae: Phytolacca
- Piperaceae: Peperomia
- Portulacaceae: Amphipetalum, Anacampseros, Avonia, Calyptrotheca, Ceraria, Cistanthe, Dendroportulaca, Grahamia, Lewisia, Parakeelya, Portulaca, Portulacaria, Schreiteria, Talinella, Talinum
- Rubiaceae: Anthorrhiza, Hydnophythum, Hydrophylax, Myrmecodia, Myrmephythum, Phylohydrax, Squamellaria
- Ruscaceae: Cordyline, Dracaena, Sansevieria
- Sapindaceae: Erythrophysa
- Saxifragaceae
- Sterculiaceae: Brachychiton, Sterculia
- Urticaceae: Laportea, Obertia, Pilea, Sarcopilea
- Viscaceae: Viscum
- Vitaceae: Cissus, Cyphostemma
- Xanthorrhoeaceae: Xanthorrhoea
- Zygophyllaceae
For some families, most members are succulent; for example the Cactaceae, Agavaceae, Aizoaceae, and Crassulaceae.
The table below shows the number of succulent species found in some families:
| Family | Succulent # | Modified parts | Distribution |
|---|---|---|---|
| Agavaceae | 300 | Leaf | North and Central America |
| Cactaceae | 1600 | Stem (root, leaf) | The Americas |
| Crassulaceae | 1300 | Leaf (root) | Worldwide |
| Aizoaceae | 2000 | Leaf | Southern Africa |
| Apocynaceae | 500 | Stem | Africa, Arabia, India |
| Didiereaceae | 11 | Stem | Madagascar (endemic) |
| Euphorbiaceae | > 1000 | Stem and/or leaf and/or root | Africa, Madagascar, Asia, the Americas, Europe, Australia |
| Asphodelaceae | 500 | Leaf | Africa, Madagascar |
| Portulacaceae | ? | Leaf and stem | The Americas |