|Winter cress, Barbarea vulgaris|
|Family:|| Brassicaceae |
Brassicaceae ( // ) or Cruciferae ( // ) is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous plants, some shrubs, with simple, although sometimes deeply incised, alternatingly set leaves without stipules or in leaf rosettes, with terminal inflorescences without bracts, containing flowers with four free sepals, four free alternating petals, two short and four longer free stamens, and a fruit with seeds in rows, divided by a thin wall (or septum).
The family contains 372 genera and 4,060 accepted species.The largest genera are Draba (440 species), Erysimum (261 species), Lepidium (234 species), Cardamine (233 species), and Alyssum (207 species).
The family contains the cruciferous vegetables, including species such as Brassica oleracea (e.g. broccoli, cabbage, cauliflower, kale, collards), Brassica rapa (turnip, Chinese cabbage, etc.), Brassica napus (rapeseed, etc.), Raphanus sativus (common radish), Armoracia rusticana (horseradish), but also a cut-flower Matthiola (stock) and the model organism Arabidopsis thaliana (thale cress).
Pieris rapae and other butterflies of the family Pieridae are some of the best-known pests of Brassicaceae species planted as commercial crops. Trichoplusia ni (cabbage looper) moth is also becoming increasingly problematic for crucifers due to its resistance to commonly used pest control methods.Some rarer Pieris butterflies, such as Pieris virginiensis , depend upon native mustards for their survival, in their native habitats. Some non-native mustards, such as garlic mustard, Alliaria petiolata , an extremely invasive species in the United States, can be toxic to their larvae.
Carl Linnaeus in 1753 regarded the Brassicaceae as a natural group, naming them "Klass" Tetradynamia. Alfred Barton Rendle placed the family in the order Rhoedales, while George Bentham and Joseph Dalton Hooker in their system published from 1862–1883, assigned it to their cohort Parietales (now the class Violales). Following Bentham and Hooker, John Hutchinson in 1948 and again in 1964 thought the Brassicaceae to stem from near the Papaveraceae. In 1994, a group of scientists including Walter Stephen Judd suggested to include the Capparaceae in the Brassicaceae. Early DNA-analysis showed that the Capparaceae—as defined at that moment—were paraphyletic, and it was suggested to assign the genera closest to the Brassicaceae to the Cleomaceae.The Cleomaceae and Brassicaceae diverged approximately 41 million years ago. All three families have consistently been placed in one order (variably called Capparales or Brassicales). The APG II system, merged Cleomaceae and Brassicaceae. Other classifications have continued to recognize the Capparaceae, but with a more restricted circumscription, either including Cleome and its relatives in the Brassicaceae or recognizing them in the segregate family Cleomaceae. The APG III system has recently adopted this last solution, but this may change as a consensus arises on this point. Current insights in the relationships of the Brassicaceae, based on a 2012 DNA-analysis, are summarized in the following tree.
Early classifications depended on morphological comparison only, but because of extensive convergent evolution, these do not provide a reliable phylogeny. Although a substantial effort was made through molecular phylogenetic studies, the relationships within the Brassicaceae have not always been well resolved yet. It has long been clear that the Aethionema are sister of the remainder of the family.One analysis from 2014 represented the relation between 39 tribes with the following tree.
The name Brassicaceae comes to international scientific vocabulary from New Latin, from Brassica , the type genus, + -aceae ,a standardized suffix for plant family names in modern taxonomy. The genus name comes from the Classical Latin word brassica , referring to cabbage and other cruciferous vegetables. The alternative older name, Cruciferae, meaning "cross-bearing", describes the four petals of mustard flowers, which resemble a cross. Cruciferae is one of eight plant family names, not derived from a genus name and without the suffix -aceae that are authorized alternative names.
Version 1 of the Plantlist website lists 349 genera.
Species belonging to the Brassicaceae are mostly annual, biennial, or perennial herbaceous plants, some are dwarf shrubs or shrubs, and very few vines. Although generally terrestrial, a few species such as water awlwort live submerged in fresh water. They may have a taproot or a sometimes woody caudex that may have few or many branches, some have thin or tuberous rhizomes, or rarely develop runners. Few species have multi-cellular glands. Hairs consist of one cell and occur in many forms: from simple to forked, star-, tree- or T-shaped, rarely taking the form of a shield or scale. They are never topped by a gland. The stems may be upright, rise up towards the tip, or lie flat, are mostly herbaceous but sometimes woody. Stems carry leaves or the stems may be leafless (in Caulanthus ), and some species lack stems altogether. The leaves do not have stipules, but there may be a pair of glands at base of leafstalks and flowerstalks. The leaf may be seated or have a leafstalk. The leaf blade is usually simple, entire or dissected, rarely trifoliolate or pinnately compound. A leaf rosette at the base may be present or absent. The leaves along the stem are almost always alternately arranged, rarely apparently opposite.The stomata are of the anisocytic type. The genome size of Brassicaceae compared to that of other Angiosperm families is very small to small (less than 3.425 million base pairs per cell), varying from 150 Mbp in Arabidopsis thaliana and Sphaerocardamum spp., to 2375 Mbp Bunias orientalis . The number of homologous chromosome sets varies from four (n=4) in some Physaria and Stenopetalum species, five (n=5) in other Physaria and Stenopetalum species, Arabidopsis thaliana and a Mathiola species, to seventeen (n=17). About 35% of the species in which chromosomes have been counted have eight sets (n=8). Due to polyploidy, some species may have up to 256 individual chromosomes, with some very high counts in the North American species of Cardamine, such as C. diphylla . Hybridisation is not unusual in Brassicaceae, especially in Arabis , Rorippa , Cardamine and Boechera . Hybridisation between species originating in Africa and California, and subsequent polyploidisation is surmised for Lepidium species native to Australia and New Zealand.
Flowers may be arranged in racemes, panicles, or corymbs, with pedicels sometimes in the axil of a bract, and few species have flowers that sit individually on flower stems that spring from the axils of rosette leaves. The orientation of the pedicels when fruits are ripe varies dependent on the species. The flowers are bisexual, star symmetrical (zygomorphic in Iberis and Teesdalia ) and the ovary positioned above the other floral parts. Each flower has four free or seldomly merged sepals, the lateral two sometimes with a shallow spur, which are mostly shed after flowering, rarely persistent, may be reflexed, spreading, ascending, or erect, together forming a tube-, bell- or urn-shaped calyx. Each flower has four petals, set alternating with the sepals, although in some species these are rudimentary or absent. They may be differentiated into a blade and a claw or not, and consistently lack basal appendages. The blade is entire or has an indent at the tip, and may sometimes be much smaller than the claws. The mostly six stamens are set in two whorls: usually the two lateral, outer ones are shorter than the four inner stamens, but very rarely the stamens can all have the same length, and very rarely species have different numbers of stamens such as sixteen to twenty four in Megacarpaea , four in Cardamine hirsuta , and two in Coronopus . The filaments are slender and not fused, while the anthers consist of two pollen producing cavities, and open with longitudinal slits. The pollen grains are tricolpate. The receptacle carries a variable number of nectaries, but these are always present opposite the base of the lateral stamens.
There is one superior pistil that consists of two carpels that may either sit directly above the base of the stamens or on a stalk. It initially consists of only one cavity but during its further development a thin wall grows that divides the cavity, both placentas and separates the two valves (a so-called false septum). Rarely, there is only one cavity without a septum. The 2–600 ovules are usually along the side margin of the carpels, or rarely at the top. Fruits are capsules that open with two valves, usually towards the top. These are called silique if at least three times longer than wide, or silicle if the length is less than three times the width. The fruit is very variable in its other traits. There may be one persistent style that connects the ovary to the globular or conical stigma, which is undivided or has two spreading or connivent lobes. The variously shaped seeds are usually yellow or brown in color, and arranged in one or two rows in each cavity. The seed leaves are entire or have a notch at the tip. The seed does not contain endosperm.
Brassicaceae have a bisymmetical corolla (left is mirrored by right, stem-side by out-side, but each quarter is not symmetrical), a septum dividing the fruit, lack stipules and have simple (although sometimes deeply incised) leaves. The sister family Cleomaceae has bilateral symmetrical corollas (left is mirrored by right, but stem-side is different from out-side), stipules and mostly palmately divided leaves, and mostly no septum.Capparaceae generally have a gynophore, sometimes an androgynophore, and a variable number of stamens.
Almost all Brassicaceae have C3 carbon fixation. The only exceptions are a few Moricandia species, which have a hybrid system between C3 and C4 carbon fixation, C4 fixation being more efficient in drought, high temperature and low nitrate availability.Brassicaceae contain different cocktails of dozens of glucosinolates. They also contain enzymes called myrosinases, that convert the glucosinolates into isothiocyanates, thiocyanates and nitriles, which are toxic to many organisms, and so help guard against herbivory.
In New Zealand and Europe the plant is commonly preyed upon by the parasite Scaptomyza flava.
Brassicaceae can be found almost on the entire land surface of the planet, but the family is absent from Antarctica, and also absent from some areas in the tropics i.e. northeastern Brazil, the Congo basin, Maritime Southeast Asia and tropical Australasia. The area of origin of the family is possibly the Irano-Turanian Region, where approximately 900 species occur in 150 different genera. About 530 of those 900 species are endemics. Next in abundance comes the Mediterranean Region, with around 630 species (290 of which are endemic) in 113 genera. The family is less prominent in the Saharo-Arabian Region—65 genera, 180 species of which 62 are endemic—and North America (comprising the North American Atlantic Region and the Rocky Mountain Floristic Region)—99 genera, 780 species of which 600 are endemic -. South-America has 40 genera containing 340 native species, Southern Africa 15 genera with over 100 species, and Australia and New-Zealand have 19 genera with 114 species between them.
Brassicaceae are almost exclusively pollinated by insects. A chemical mechanism in the pollen is active in many species to avoid selfing. Two notable exceptions are exclusive self pollination in closed flowers in Cardamine chenopodifolia , and wind pollination in Pringlea antiscorbutica .Although it can be pollinated, Alliaria petiolata is self-fertile. Most species reproduce sexually through seed, but Cardamine bulbifera produces gemmae and in others, such as Cardamine pentaphyllos , the coral-like roots easily break into segments, that will grow into separate plants. In some species, such as in the genus Cardamine , seed pods open with force and so catapult the seeds quite far. Many of these have sticky seed coats, assisting long distance dispersal by animals, and this may also explain several intercontinental dispersal events in the genus, and its near global distribution. Brassicaceae are common on serpentine and dolomite rich in magnesium. Over a hundred species in the family accumulate heavy metals, particularly zinc and nickel, which is a record percentage. Several Alyssum species can accumulate nickel up to 0.3% of their dry weight, and may be useful in soil remediation or even bio-mining.
Brassicaceae contain glucosinolates as well as myrosinases inside their cells. When the cell is damaged, the myrosinases hydrolise the glucosinolates, leading to the synthesis of isothiocyanates, which are compounds toxic to most animals, fungi and bacteria. Some insect herbivores have developed counter adaptations such as rapid absorption of the glucosinates, quick alternative breakdown into non-toxic compounds and avoiding cell damage. In the whites family (Pieridae), one counter mechanisme involves glucosinolate sulphatase, which changes the glucosinolate, so that it cannot be converted to isothiocyanate. A second is that the glucosinates are quickly broken down, forming nitriles.Differences between the mixtures of glucosinolates between species and even within species is large, and individual plants may produce in excess of fifty individual substances. The energy penalty for synthesising all these glucosinolates may be as high as 15% of the total needed to produce a leaf. Bittercress (Barbarea vulgaris) also produces triterpenoid saponins. These adaptations and counter adaptations probably have led to extensive diversification in both the Brassicaceae and one of its major pests, the butterfly family Pieridae. A particular cocktail of volatile glucosinates triggers egg-laying in many species. Thus a particular crop can sometimes be protected by planting bittercress as a deadly bait, for the saponins kill the caterpillars, but the butterfly is still lured by the bittercress to lay its egg on the leaves. A moth that feeds on a range of Brassicaceae is the diamondback moth (Plutella xylostella). Like the Pieridae, it is capable of converting isothiocyanates into less problematic nitriles. Managing this pest in crops became more complicated after resistance developed against a toxin produced by Bacillus thuringiensis , which is used as a wide spectrum biological plant protection against caterpillars. Parasitoid wasps that feed on such insect herbivores are attracted to the chemical compounds released by the plants, and thus are able to locate their prey. The cabbage aphid (Brevicoryne brassicae) stores glucosinolates and synthesises its own myrosinases, which may deter its potential predators.
Since its introduction in the 19th century, Alliaria petiolata has been shown to be extremely successful as an invasive species in temperate North America due, in part, to its secretion of allelopathic chemicals. These inhibit the germination of most competing plants and kill beneficial soil fungi needed by many plants, such as many tree species, to successfully see their seedlings grow to maturity. The monoculture formation of an herb layer carpet by this plant has been shown to dramatically alter forests, making them wetter, having fewer and fewer trees, and having more vines such as poison ivy ( Toxicodendron radicans ). The overall herb layer biodiversity is also drastically reduced, particularly in terms of sedges and forbs. Research has found that removing 80 percent of the garlic mustard infestation plants did not lead to a particularly significant recovery of that diversity. Instead, it required around 100 percent removal. Given that not one of an estimated 76 species that prey on the plant has been approved for biological control in North America and the variety of mechanisms the plant has to ensure its dominance without them (e.g. high seed production, self-fertility, allelopathy, spring growth that occurs before nearly all native plants, roots that break easily when pulling attempts are made, a complete lack of palatability for herbivores at all life stages, etc.) it is unlikely that such a high level of control can be established and maintained on the whole.It is estimated that adequate control can be achieved with the introduction of two European weevils, including one that is monophagous. However, the USDA's TAG group has blocked these introductions since 2004. In addition to being invasive, garlic mustard also is a threat to native North American Pieris butterflies such as Pieris oleracea , as they preferentially oviposit on it, although it is toxic to their larvae.
This family includes important agricultural crops, among which many vegetables such as cabbage, broccoli, cauliflower, kale, Brussels sprouts, collard greens, Savoy, kohlrabi, and gai lan ( Brassica oleracea ), turnip, napa cabbage, bomdong, bok choy and rapini ( Brassica rapa ), rocket salad/arugula ( Eruca sativa ), garden cress ( Lepidium sativum ), watercress ( Nasturtium officinale ) and radish ( Raphanus ) and a few spices like horseradish ( Armoracia rusticana ), Brassica, wasabi ( Eutrema japonicum ), white, Indian and black mustard ( Sinapis alba , Brassica juncea and B. nigra respectively). Vegetable oil is produced from the seeds of several species such as Brassica napus (rapeseed oil), perhaps providing the largest volume of vegetable oils of any species. Woad ( Isatis tinctoria ) was used in the past to produce a blue textile dye (indigo), but has largely been replaced by the same substance from unrelated tropical species like Indigofera tinctoria .
Brassinosteroids are growing in agricultural and gardening importance.
The Brassicaceae also includes ornamentals, such as species of Aethionema , Alyssum , Arabis , Aubrieta , Aurinia , Cheiranthus , Erysimum , Hesperis , Iberis , Lobularia , Lunaria , Malcolmia , and Matthiola .Honesty ( Lunaria annua ) is cultivated for the decorative value of the translucent remains of the fruits after drying. However, it can be a pest species in areas where it is not native.
The small Eurasian weed Arabidopsis thaliana is widely used as model organism in the study of the molecular biology of flowering plants (Angiospermae).
Some species are useful as food plants for Lepidoptera, such as certain wild mustard and cress species, such as Turritis glabra and Boechera laevigata that are utilized by several North American butterflies.Garlic mustard, Alliaria petiolata , is one of the most aggressive and damaging invasive species in North America. Invasive aggressive mustard species are known for being self-fertile, seeding very heavily with small seeds that have a lengthy lifespan coupled with a very high rate of viability and germination, and for being completely unpalatable to both herbivores and insects in areas to which they are not native. Garlic mustard is toxic to several rarer North American Pieris species.
The Brassicales are an order of flowering plants, belonging to the eurosids II group of dicotyledons under the APG II system. One character common to many members of the order is the production of glucosinolate compounds. Most systems of classification have included this order, although sometimes under the name Capparales.
Erysimum, or wallflower, is a genus of flowering plants in the cabbage family, Brassicaceae. It includes more than 150 species, both popular garden plants and many wild forms. The genus Cheiranthus is sometimes included here in whole or in part. Erysimum has since the early 21st century been ascribed to a monogeneric cruciferous tribe, Erysimeae, characterised by sessile, stellate (star-shaped) and/or malpighiaceous (two-sided) trichomes, yellow to orange flowers and multiseeded siliques.
Brassica is a genus of plants in the cabbage and mustard family (Brassicaceae). The members of the genus are informally known as cruciferous vegetables, cabbages, or mustard plants. Crops from this genus are sometimes called cole crops—derived from the Latin caulis, denoting the stem or stalk of a plant.
Alliaria petiolata, or garlic mustard, is a biennial flowering plant in the mustard family (Brassicaceae). It is native to Europe, western and central Asia, north-western Africa, Morocco, Iberia and the British Isles, north to northern Scandinavia, and east to northern Pakistan and Xinjiang in western China.
Pieris rapae is a small- to medium-sized butterfly species of the whites-and-yellows family Pieridae. It is known in Europe as the small white, in North America as the cabbage white or cabbage butterfly,, on several continents as the small cabbage white, and in New Zealand simply as the white butterfly. The butterfly is recognizable by its white color with small black dots on its wings, and it can be distinguished from P. brassicae by the smaller size and lack of the black band at the tip of their forewings.
The term mustard oil is used for two different oils that are made from mustard seeds:
Pieris, the whites or garden whites, is a widespread now almost cosmopolitan genus of butterflies of the family Pieridae. The highest species diversity is in the Palearctic, with a higher diversity in Europe and eastern North America than the similar and closely related Pontia. The females of many Pieris butterflies are UV reflecting, while the male wings are strongly UV absorbing due to pigments in the scales.
Pieris oleracea, or more commonly known as the mustard white, is a butterfly in the family Pieridae native to a large part of Canada and the northeastern United States. The nearly all-white butterfly is often found in wooded areas or open plains. There are two seasonal forms, which make it distinct from other similar species. Because of climate change, populations are moving further north.
Choy sum is a leafy vegetable commonly used in Chinese cuisine. It is a member of the genus Brassica of the mustard family, Brassicaceae. Choy sum is a transliteration of the Cantonese name, which can be literally translated as "heart of the vegetable". It is also known as Chinese flowering cabbage.
Glucosinolates are natural components of many pungent plants such as mustard, cabbage, and horseradish. The pungency of those plants is due to mustard oils produced from glucosinolates when the plant material is chewed, cut, or otherwise damaged. These natural chemicals most likely contribute to plant defence against pests and diseases, and impart a characteristic bitter flavor property to cruciferous vegetables.
Sinigrin is a glucosinolate that belongs to the family of glucosides found in some plants of the family Brassicaceae such as Brussels sprouts, broccoli, and the seeds of black mustard. Whenever sinigrin-containing plant tissue is crushed or otherwise damaged, the enzyme myrosinase degrades sinigrin to a mustard oil, which is responsible for the pungent taste of mustard and horseradish. Seeds of white mustard, Sinapis alba, will give a much less pungent mustard because this species contains a different glucosinolate, sinalbin.
Cruciferous vegetables are vegetables of the family Brassicaceae with many genera, species, and cultivars being raised for food production such as cauliflower, cabbage, kale, garden cress, bok choy, broccoli, Brussels sprouts, and similar green leaf vegetables. The family takes its alternative name from the shape of their flowers, whose four petals resemble a cross.
The Capparaceae, commonly known as the caper family, are a family of plants in the order Brassicales. As currently circumscribed, the family contains 33 genera and about 700 species. The largest genera are Capparis, Maerua, Boscia and Cadaba.
Myrosinase is a family of enzymes involved in plant defense against herbivores, specifically the mustard oil bomb. The three-dimensional structure has been elucidated and is available in the PDB.
The Cleomaceae are a small family of flowering plants in the order Brassicales, comprising about 300 species in 10 genera, or about 150 species in 17 genera. These genera were previously included in the family Capparaceae, but were raised to a distinct family when DNA evidence suggested the genera included in it are more closely related to the Brassicaceae than they are to the Capparaceae. The APG II system allows for Cleomaceae to be included in Brassicaceae.
Erysimum cheiranthoides, the treacle-mustard,wormseed wallflower, or wormseed mustard is a species of Erysimum native to most of central and northern Europe and northern and central Asia. Like other Erysimum species, E. cheiranthoides accumulates two major classes of defensive chemicals, glucosinolates and cardiac glycosides.
Brevicoryne brassicae, commonly known as the cabbage aphid or cabbage aphis, is a destructive aphid native to Europe that is now found in many other areas of the world. The aphids feed on many varieties of produce, including cabbage, broccoli (especially), Brussels sprouts, cauliflower and many other members of the genus Brassica, but do not feed on plants outside of the family Brassicaceae. The insects entirely avoid plants other than those of Brassicaceae; even though thousands may be eating broccoli near strawberries, the strawberries will be left untouched.
The mustard oil bomb, formerly known as the glucosinolate–myrosinase complex, is a chemical herbivory defense system found in members of the Brassicaceae. The mustard oil bomb requires the activation of a common plant secondary metabolite, glucosinolate, by an enzyme, myrosinase. The defense complex is typical among plant defenses to herbivory in that the two molecules are stored in different compartments in the leaves of plants until the leaf is torn by an herbivore. The glucosinolate has a β-glucose and a sulfated oxime. The myrosinase removes the β-glucose to form mustard oils that are toxic to herbivores. The defense system was named a "bomb" by Matile, because it like a real bomb is waiting to detonate upon disturbance of the plant tissue.
Garlic mustard was introduced to North America as a culinary herb in the 1860s and it is considered an invasive species in much of North America. As of 2020 it has been documented in most of the Eastern United States and Canada, with scattered populations in the west. It is listed as a noxious or restricted plant in the following states: Alabama, Connecticut, Massachusetts, Minnesota, New Hampshire, Oregon, Vermont, and Washington. A current map of its distribution in the United States can be found at the Early Detection and Distribution Mapping System (EDDmapS).