Acanthaceae () is a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

(the acanthus family) of

dicotyledon The dicotyledons, also known as dicots (or, more rarely, dicotyls), are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, ...

ous

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s containing almost 250 genera and about 2500 species. Most are

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

herbs Herbs are a widely distributed and widespread group of plants, excluding vegetables, with savory or aromatic properties that are used for flavoring and garnish (food), garnishing food, for medicinal purposes, or for fragrances. Culinary use typi ...

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

s, or twining vines; some are

epiphytes An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphyt ...

. Only a few species are distributed in

temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...

regions. The four main centres of distribution are

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

and

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

, and

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

. Representatives of the family can be found in nearly every

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

, including dense or open

forest A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...

scrubland Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominance (ecology), dominated by shrubs, often also including grasses, herbaceous plant, herbs, and geophytes. Shrubland may either occur naturally o ...

s, wet fields and valleys, sea

coast A coast (coastline, shoreline, seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, su ...

and marine areas,

swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

s, and

mangrove A mangrove is a shrub or tree that grows mainly in coastal saline water, saline or brackish water. Mangroves grow in an equatorial climate, typically along coastlines and tidal rivers. They have particular adaptations to take in extra oxygen a ...

forests.

Description

Plants in this family have simple, opposite,

decussate Decussation is used in biological contexts to describe a crossing (due to the shape of the Roman numeral for ten, an uppercase 'X' (), ). In Latin anatomical terms, the form is used, e.g. . Similarly, the anatomical term chiasma is named aft ...

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

with entire (or sometimes toothed, lobed, or spiny) margins, and without

stipule In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole (botany), petiole). They are primarily found among dicots and rare among monocots. Stipules are considered part ...

s. The leaves may contain

cystolith Cystolith (Gr. "cavity" and "stone") is a botanical term for outgrowths of the epidermal cell wall, usually of calcium carbonate but sometimes of silicon dioxide also, formed in a cellulose matrix in special cell (biology), cells called lithocys ...

calcium carbonate Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...

concretions, seen as streaks on the surface. The

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s are perfect,

zygomorphic Floral symmetry describes whether, and how, a flower, in particular its perianth, can be divided into two or more identical or mirror-image parts. Uncommonly, flowers may have no axis of symmetry at all, typically because their parts are spir ...

to nearly

actinomorphic Floral symmetry describes whether, and how, a flower, in particular its perianth, can be divided into two or more identical or mirror-image parts. Uncommonly, flowers may have no axis of symmetry at all, typically because their parts are spirall ...

, and arranged in an

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

that is either a

spike Spike, spikes, or spiking may refer to: Arts, entertainment, and media Books * ''The Spike'' (novel), a novel by Arnaud de Borchgrave * ''The Spike'' (Broderick book), a nonfiction book by Damien Broderick * ''The Spike'', a starship in Peter ...

raceme A raceme () or racemoid is an unbranched, indeterminate growth, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are ...

, or cyme. Typically, a colorful

bract In botany, a bract is a modified or specialized leaf, associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves in size, color, shape or texture. They also lo ...

subtends each flower; in some species, the bract is large and showy. The

calyx CALYX, Inc. is a non-profit publisher of art and literature by women founded in 1976 based in Corvallis, Oregon. CALYX publishes both '' CALYX, A Journal of Art and Literature by Women'' twice a year and CALYX Books, which publishes one to three ...

usually has four or five lobes; the corolla tubular, two-lipped or five-lobed;

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s number either two or four, arranged in pairs and inserted on the corolla, and the

ovary The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/ oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are end ...

is superior and bicarpellated, with axile

placentation Placentation is the formation, type and structure, or modes of arrangement of the placenta. The function of placentation is to transfer nutrients, respiratory gases, and water from maternal tissue to a growing embryo, and in some instances to re ...

. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

is a two-celled capsule,

dehiscing Dehiscence is the splitting of a mature plant structure along a built-in line of weakness to release its contents. This is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part. Structures that op ...

somewhat explosively. In most species, the

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

s are attached to a small, hooked stalk (a modified

funiculus Funiculus (''Latin'' for "slender rope") is any cord-like structure in anatomy or biology, and may refer to: Anatomy * the spermatic cord formed by the vas deferens and surrounding tissue * the umbilical cord attaching a fetus to the placenta dur ...

called a jaculator or a retinaculum) that ejects them from the capsule. This trait is shared by all members of the clade

Acanthoideae Acanthoideae is a subfamily of plants in the family Acanthaceae. Tribes and genera Wikispecies lists the following genera in six tribes: Acantheae * '' Acanthopsis'' * '' Acanthus'' * '' Achyrocalyx'' * '' Aphelandra'' * '' Blepharis'' * '' Cros ...

. A 1995 study of seed expulsion in Acanthaceae used high speed video pictures to show that retinacula propel seeds away from the parent plant when the fruits dehisce, thereby helping the plant gain maximum

seed dispersal In spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant. Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors, ...

range. A species well known to

gardeners is bear's breeches (''

Acanthus mollis ''Acanthus mollis'', commonly known as bear's breeches, sea dock, bear's foot plant, sea holly, gator plant or oyster plant, is a species of plant in the family Acanthaceae and is native to the Mediterranean region. It is a leafy, clump-forming ...

''), a herbaceous

perennial plant In horticulture, the term perennial (''wikt:per-#Prefix, per-'' + ''wikt:-ennial#Suffix, -ennial'', "through the year") is used to differentiate a plant from shorter-lived annual plant, annuals and biennial plant, biennials. It has thus been d ...

with big leaves and flower spikes up to 2 m tall.

Tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

genera familiar to gardeners include ''

Thunbergia ''Thunbergia'' is a genus of flowering plants in the family Acanthaceae. It includes 150 species native to tropical and subtropical regions of sub-Saharan Africa, Madagascar, southern Asia, New Guinea, and Australia. ''Thunbergia'' species are ...

'' and '' Justicia''. ''

Avicennia ''Avicennia'' is a genus of flowering plants currently placed in the bear's breeches family, Acanthaceae. It contains mangrove trees, which occur in the intertidal zones of estuarine areas and are characterized by its "pencil roots", which ar ...

'', a genus of

trees, usually placed in

Verbenaceae The Verbenaceae ( ), the verbena family or vervain family, is a family of mainly tropical flowering plants. It contains trees, shrubs, and herbs notable for heads, spikes, or clusters of small flowers, many of which have an aromatic smell. T ...

or in its own family,

Avicenniaceae ''Avicennia'' is a genus of flowering plants currently placed in the bear's breeches family, Acanthaceae. It contains mangrove trees, which occur in the intertidal zones of estuarine areas and are characterized by its "pencil roots", which ar ...

, is included in Acanthaceae by the

Angiosperm Phylogeny Group The Angiosperm Phylogeny Group (APG) is an informal international group of systematic botanists who collaborate to establish a consensus on the taxonomy of flowering plants (angiosperms) that reflects new knowledge about plant relationships disc ...

on the basis of

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

studies that show it to be associated with this family.

Medicinal uses

Traditionally the most important part use in Acanthaceae is the leaves and they are used externally for wounds. Some research has indicated that Acanthaceae possess

antifungal An antifungal medication, also known as an antimycotic medication, is a pharmaceutical fungicide or fungistatic used to treat and prevent mycosis such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as ...

cytotoxic Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are toxic metals, toxic chemicals, microbe neurotoxins, radiation particles and even specific neurotransmitters when the system is out of balance. Also some types of dr ...

anti-inflammatory Anti-inflammatory is the property of a substance or treatment that reduces inflammation, fever or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs reduce pain by inhibiting mechan ...

anti-pyretic An antipyretic (, from ''anti-'' 'against' and ' 'feverish') is a substance that reduces fever. Antipyretics cause the hypothalamus to override a prostaglandin-induced increase in temperature. The body then works to lower the temperature, which r ...

antioxidant Antioxidants are Chemical compound, compounds that inhibit Redox, oxidation, a chemical reaction that can produce Radical (chemistry), free radicals. Autoxidation leads to degradation of organic compounds, including living matter. Antioxidants ...

insecticidal Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, in ...

hepatoprotective Hepatoprotection or antihepatotoxicity is the ability of a chemical substance to prevent damage to the liver. This is opposite to hepatotoxicity. Hepatoprotective molecules used in emergency medicine * Acetylcysteine is considered the hepatopr ...

immunomodulatory Immunotherapy or biological therapy is the treatment of disease by activating or suppressing the immune system. Immunotherapies designed to elicit or amplify an immune response are classified as ''activation immunotherapies,'' while immunothera ...

, anti-platelet aggregation and anti-viral potential. For instance, '' Acanthus ilicifolius'', whose chemical composition has been heavily researched, is widely used in ethnopharmaceutical applications, including in Indian and Chinese

traditional medicine Traditional medicine (also known as indigenous medicine or folk medicine) refers to the knowledge, skills, and practices rooted in the cultural beliefs of various societies, especially Indigenous groups, used for maintaining health and treatin ...

. Various parts of ''Acanthus ilicifolius'' have been used to treat

asthma Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...

diabetes Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or the cells of th ...

leprosy Leprosy, also known as Hansen's disease (HD), is a Chronic condition, long-term infection by the bacteria ''Mycobacterium leprae'' or ''Mycobacterium lepromatosis''. Infection can lead to damage of the Peripheral nervous system, nerves, respir ...

hepatitis Hepatitis is inflammation of the liver parenchyma, liver tissue. Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (jaundice), Anorexia (symptom), poor appetite ...

snake bites A snakebite is an injury caused by the bite of a snake, especially a venomous snake. A common sign of a bite from a venomous snake is the presence of two puncture wounds from the animal's fangs. Sometimes venom injection from the bite may oc ...

, and

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects synovial joint, joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and h ...

. The leaves of ''

Acanthus ebracteatus ''Acanthus ebracteatus'' is a species of shrubby herb that grows in the undergrowth of mangroves of south-east Asia. Common names include sea holly and holly mangrove. Description It grows as an erect, spreading or scrambling shrubby herb, up t ...

'', noted for their

properties, are used for making Thai herbal tea in

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

and

Phytochemistry

Phytochemical reports on family Acanthaceae are

glycosides In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. ...

flavonoids Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

, benzonoids,

phenolic compounds In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (− O H) bonded directly to an aromatic hydrocarbon group. The simplest is phenol, . Phenolic compounds are c ...

naphthoquinone Naphthoquinones constitute a class of organic compounds structurally related to naphthalene. Two isomers are common for the parent naphthoquinones: * 1,2-Naphthoquinone * 1,4-Naphthoquinone Natural products * Alkannin * Hexahydroxy-1,4-nap ...

and

triterpenoids Triterpenes are a class of terpenes composed of six isoprene units with the molecular formula C30H48; they may also be thought of as consisting of three terpene units. Animals, plants and fungi all produce triterpenes, including squalene, the pre ...

Overview of systematics

Since the first comprehensive classification of Acanthaceae in 1847 by

Nees Christian Gottfried Daniel Nees von Esenbeck (14 February 1776 – 16 March 1858) was a prolific German botanist, physician, zoologist, and natural philosopher. He was a contemporary of Goethe and was born within the lifetime of Linnaeus. ...

, there have been a few major revisions presented since for the whole family.

Lindau Lindau (, ''Lindau am Bodensee''; ; Low Alemannic German, Low Alemannic: ''Lindou'') is a major Town#Germany, town and Lindau (island), island on the eastern side of Lake Constance (''Bodensee'' in German) in Bavaria, Germany. It is the capital ...

, in 1895, divided the family into the subfamilies Mendoncioideae,

Thunbergioideae Thunbergioideae is a subfamily of plants in the family Acanthaceae Acanthaceae () is a Family (biology), family (the acanthus family) of dicotyledonous flowering plants containing almost 250 genera and about 2500 species. Most are Tropics, tro ...

Nelsonioideae Nelsonioideae is a subfamily of plants in the family Acanthaceae Acanthaceae () is a Family (biology), family (the acanthus family) of dicotyledonous flowering plants containing almost 250 genera and about 2500 species. Most are Tropics, tropi ...

, and

. Critically, Mendoncioideae, Thunbergioideae, and Nelsonioideae do not possess retinaculate fruits—and it is this distinction, between classifying Acanthaceae into a family that includes those clades with non-retinaculate fruits and one that excludes them, that still persists to the modern day. Bremekamp, in 1965, presented a classification of Acanthaceae that differed from that of Lindau, for his Acanthaceae excluded genera that lack retinaculate fruits. He placed Nelsonioideae within

Scrophulariaceae The Scrophulariaceae are a family of flowering plants, commonly known as the figwort family. The plants are annual and perennial herbs, as well as shrubs. Flowers have bilateral (zygomorphic) or rarely radial (actinomorphic) symmetry. The Scr ...

, classified Thunbergiaceae and Mendonciaceae as distinct families and divided his Acanthaceae into two groups (Acanthoideae and Ruelloideae) based on the presence or absence of

s, articulate stems, monothecate

anthers The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filamen ...

, and colpate

pollen Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...

. In Scotland and Vollesen's 2000 study, they accepted 221

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

and detailed five major groups within Acanthaceae s.s. (that is, those possessing retinaculate fruits), which is equivalent to Acanthoideae Link sensu Lindau 1895. Out of those 221 genera, they placed 201 of them into seven infrafamilial taxa of Acanthaceae, leaving only 20 unplaced. In the current understanding of Acanthaceae, Acanthaceae s.s. includes only those

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

s with retinaculate fruits (that is, Acantheae, Barlerieae, Andrographideae, Whitfieldeae,

Ruellieae Acanthoideae is a subfamily of plants in the family Acanthaceae. Tribes and genera Wikispecies lists the following genera in six tribes: Acantheae * ''Acanthopsis'' * ''Acanthus'' * '' Achyrocalyx'' * ''Aphelandra'' * ''Blepharis'' * '' Crossand ...

, and Justiceae), while Acanthaceae s.l. includes those clades as well as Thunbergioideae, Nelsonioideae, and ''

.''

Dating the Acanthaceae lineage

Much research, using both molecular data and

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s, has been conducted in recent years regarding the dating and distribution of the Acanthaceae and

Lamiales The Lamiales (also known as the mint order) are an order of flowering plants in the asterids clade of the Eudicots. Under the APG IV system of flowering plant classification the order consists of 24 families, and includes about 23,810 species ...

lineage, although there still remains some ambiguity. In a 2004 study on the molecular phylogenetic dating of asterid flowering plants, researchers estimated 106 million years (MY) for the stem lineage of Lamiales, 67 MY for the stem lineage of Acanthaceae, and 54 MY for the crown node of Acanthaceae (that is, the age of extant lineages with the family). These estimates are older than those based on fossils that can confidently be assigned to Lamiales, which are middle

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

in age, ca. 48-37 MY.

Palynomorphs Palynology is the study of microorganisms and microscopic fragments of mega-organisms that are composed of acid-resistant organic material and occur in sediments, sedimentary rocks, and even some metasedimentary rocks. Palynomorphs are the mic ...

that definitively show the existence of Acanthaceae are known from the upper

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

, with the oldest ca. 22 MY.

Genera

Asystasia gangetica in Hyderabad W IMG 4769

, the

Germplasm Resources Information Network Germplasm Resources Information Network or GRIN is an online USDA National Genetic Resources Program software project to comprehensively manage the computer database for the holdings of all plant germplasm collected by the National Plant Germpla ...

accepts 217 genera. As of January 2024,

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

accepts 207 genera.

Excluded genera

* '' Thomandersia'' Baill. → Thomandersiaceae

References

External links

Tree of Life Acanthaceae

Flowers in Israel.

i

{{Authority control Lamiales families