''Linaria'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of ...

perennials In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

, and the largest genus in the

Antirrhineae The Antirrhineae are one of the 12 tribes of the family Plantaginaceae. It contains the toadflax relatives, such as snapdragons. Description and uses Most Antirrhineae are herbaceous, short-lived, perennial or annual plants growing at most ...

tribe of the plantain family

Plantaginaceae Plantaginaceae, the plantain family or veronica family, is a large, diverse family (biology), family of flowering plants in the order Lamiales that includes common flowers such as Antirrhinum, snapdragon and Digitalis, foxglove. It is unrelated ...

Taxonomy

''Linaria'' was traditionally placed in the family

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 ...

Phylogenetic analysis In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data ...

has now placed it in the vastly expanded family

. Closely related genera include ''

Nuttallanthus ''Nuttallanthus'' is a genus of four species of herbaceous annuals and perennials that was traditionally placed in the foxglove family Scrophulariaceae. Due to new genetic research, it has now been placed in the vastly expanded family Plantagina ...

'' (American toadflaxes, recently split from ''Linaria''), ''

Antirrhinum ''Antirrhinum'' is a genus of plants in the Plantaginaceae family, commonly known as dragon flowers or snapdragons because of the flowers' fancied resemblance to the face of a dragon that opens and closes its mouth when laterally squeezed. They ...

'' (snapdragons) and '' Cymbalaria'' (ivy-leaved toadflaxes).

Cultivation

Several ''Linaria'' species are cultivated as garden plants, and some are regarded as having a weedy habit. *Common toadflax or butter-and-eggs (''

Linaria vulgaris ''Linaria vulgaris'', the common toadflax,Blamey, M. & Grey-Wilson, C. (1989). ''Flora of Britain and Northern Europe''. yellow toadflax or butter-and-eggs, is a species of flowering plant in the family Plantaginaceae, native to Europe, Siberia ...

''), a European species which is widely introduced elsewhere and grows as a common weed in some areas. *Broomleaf toadflax or Dalmatian toadflax ('' Linaria genistifolia'', syn. ''L. dalmatica''), a native of southeast Europe that has become a weed in parts of North America.Dalmatian Toadflax (''Linaria dalmatica'').
National Invasive Species Information Center,

United States National Agricultural Library The United States National Agricultural Library (NAL) is one of the world's largest agricultural research libraries, and serves as a national library of the United States and as the library of the United States Department of Agriculture. Locate ...

. *Purple toadflax (''

Linaria purpurea ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are Annual plant, annuals and herbaceous Perennial plant, perennials, and the largest genus in the Antirrhineae tribe ...

''), a species native to the

Mediterranean The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern ...

region grown as a

garden A garden is a planned space, usually outdoors, set aside for the cultivation, display, and enjoyment of plants and other forms of nature. The single feature identifying even the wildest wild garden is ''control''. The garden can incorporate bot ...

plant for its dark purple or pink flowers. The version with purple flowers can be mistaken for lavender. Spreads readily. *Pale toadflax ('' Linaria repens''), a species from western Europe similar to ''L. purpurea'', but with paler flowers. *Alpine toadflax ('' Linaria alpina''), purple flowers with orange (or purple) lobes in the center. *Moroccan toadflax (''

Linaria maroccana ''Linaria maroccana'' is a species of flowering plant in the plantain family known by the common names Moroccan toadflax and annual toadflax. It is native to Morocco, but it can be found elsewhere growing wild as an introduced species, such as C ...

''), the flower has five lobes arranged into two lips with a spur at the end, often purple with white.

Species

The following species are recognised in the genus ''Linaria'': *''

Linaria accitensis ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *''

Linaria acutiloba ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *''

Linaria aeruginea ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *''

Linaria afghanica ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *''

Linaria alaica ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *''

Linaria albifrons ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *''

Linaria algarviana ''Linaria algarviana'' is a species of toadflax in the plantain family Plantaginaceae, endemic to southern Portugal, specifically the western portion of the Algarve The Algarve (, , ) is the southernmost NUTS statistical regions of Portugal, ...

'' *'' Linaria alpina'' *''

Linaria altaica ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *''

Linaria amethystea ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *''

Linaria amoi ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *'' Linaria angustissima'' *'' Linaria antilibanotica'' *'' Linaria arcusangeli'' *''

Linaria arenaria ''Linaria arenaria'', sometimes called sand toadflax or French toadflax, is a yellow-flowered member of the genus ''Linaria''. It is found in sand-dunes and sandy grassland in western France, north-west Spain and Portugal and is thus a psammophyt ...

'' *'' Linaria arenicola'' *'' Linaria argillicola'' *'' Linaria armeniaca'' *'' Linaria arvensis'' *'' Linaria atlantica'' *'' Linaria azerbaijanensis'' *'' Linaria badachschanica'' *'' Linaria badalii'' *'' Linaria bamianica'' *'' Linaria becerrae'' *'' Linaria bessarabica'' *'' Linaria biebersteinii'' *'' Linaria bipartita'' *'' Linaria bipunctata'' *'' Linaria bordiana'' *'' Linaria boushehrensis'' *'' Linaria brachyphylla'' *'' Linaria bubanii'' *'' Linaria bungei'' *'' Linaria buriatica'' *'' Linaria caesia'' *'' Linaria capraria'' *'' Linaria cavanillesii'' *'' Linaria chalepensis'' *'' Linaria clementei'' *'' Linaria confertiflora'' *'' Linaria corifolia'' *'' Linaria × cornubiensis'' *'' Linaria cossoniana'' *'' Linaria cossonii'' *'' Linaria cretacea'' *''

Linaria dalmatica ''Linaria dalmatica'' is a herbaceous, short-lived perennial plant native to western Asia and southeastern Europe that has become a weed in other areas. The family this plant now belongs to is the Plantaginaceae Family. Previously, it belonged to ...

'' *'' Linaria damascena'' *'' Linaria decipiens'' *'' Linaria depauperata'' *'' Linaria diffusa'' *'' Linaria dissita'' *'' Linaria × dominii'' *'' Linaria dumanii'' *'' Linaria elegans'' *'' Linaria elymaitica'' *''

Linaria fallax ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *'' Linaria farsensis'' *'' Linaria fastigiata'' *'' Linaria faucicola'' *'' Linaria fedorovii'' *'' Linaria ficalhoana'' *''

Linaria flava ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *'' Linaria genistifolia'' *'' Linaria gharbensis'' *'' Linaria glacialis'' *'' Linaria glauca'' *'' Linaria golestanensis'' *'' Linaria grandiflora'' *'' Linaria griffithii'' *'' Linaria grjunerae'' *'' Linaria guilanensis'' *'' Linaria haelava'' *'' Linaria hepatica'' *'' Linaria heratensis'' *'' Linaria hirta'' *'' Linaria hohenackeri'' *'' Linaria huteri'' *'' Linaria × hybrida'' *'' Linaria iconia'' *'' Linaria ikonnikovii'' *'' Linaria imzica'' *'' Linaria incarnata'' *'' Linaria incompleta'' *'' Linaria intricata'' *'' Linaria iranica'' *'' Linaria × jalancina'' *'' Linaria japonica'' *'' Linaria jaxartica'' *'' Linaria joppensis'' *'' Linaria kavirensis'' *'' Linaria khalkhalensis'' *'' Linaria khorasanensis'' *'' Linaria × kocianovichii'' *'' Linaria kokanica'' *'' Linaria kulabensis'' *'' Linaria kurdica'' *'' Linaria latifolia'' *'' Linaria laxiflora'' *'' Linaria leptoceras'' *''

Linaria lineolata ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *'' Linaria loeselii'' *'' Linaria longicalcarata'' *'' Linaria macrophylla'' *'' Linaria macroura'' *''

'' *'' Linaria maymanica'' *'' Linaria mazandaranensis'' *'' Linaria melampyroides'' *'' Linaria melanogramma'' *'' Linaria meyeri'' *'' Linaria michauxii'' *'' Linaria micrantha'' *'' Linaria microsepala'' *'' Linaria multicaulis'' *'' Linaria munbyana'' *'' Linaria musilii'' *'' Linaria nachitschevanica'' *'' Linaria nigricans'' *'' Linaria nivea'' *'' Linaria nurensis'' *'' Linaria nuristanica'' *'' Linaria oblongifolia'' *'' Linaria odora'' *'' Linaria oligantha'' *'' Linaria × oligotricha'' *'' Linaria onubensis'' *'' Linaria orbensis'' *'' Linaria ordubadica'' *'' Linaria pamirica'' *'' Linaria paradoxa'' *'' Linaria parviracemosa'' *'' Linaria pedicellata'' *'' Linaria pedunculata'' *''

Linaria pelisseriana ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *'' Linaria peloponnesiaca'' *'' Linaria peltieri'' *'' Linaria pinifolia'' *'' Linaria platycalyx'' *'' Linaria polygalifolia'' *'' Linaria popovii'' *'' Linaria propinqua'' *'' Linaria pseudolaxiflora'' *'' Linaria pseudoviscosa'' *''

'' *'' Linaria pyramidalis'' *'' Linaria qartobensis'' *'' Linaria quasisessilis'' *'' Linaria reflexa'' *'' Linaria remotiflora'' *'' Linaria repens'' *'' Linaria ricardoi'' *'' Linaria riffea'' *'' Linaria × rocheri'' *'' Linaria rubioides'' *'' Linaria sabulosa'' *'' Linaria salangensis'' *'' Linaria salzmannii'' *'' Linaria saposhnikovii'' *'' Linaria saturejoides'' *'' Linaria saxatilis'' *'' Linaria schelkownikowii'' *'' Linaria schirvanica'' *'' Linaria semialata'' *'' Linaria × sepium'' *'' Linaria sessilis'' *'' Linaria simplex'' *'' Linaria spartea'' *'' Linaria striatella'' *'' Linaria supina'' *'' Linaria tarhunensis'' *'' Linaria tenuis'' *'' Linaria thibetica'' *'' Linaria thymifolia'' *'' Linaria tingitana'' *'' Linaria tonzigii'' *'' Linaria triornithophora'' *'' Linaria triphylla'' *'' Linaria tristis'' *''

Linaria tursica ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *'' Linaria unaiensis'' *''

Linaria × valdesiana ''Linaria'' is a genus of almost 200 species of flowering plants, one of several related groups commonly called toadflax. They are annuals and herbaceous perennials, and the largest genus in the Antirrhineae tribe of the plantain family Plantag ...

'' *'' Linaria venosa'' *'' Linaria ventricosa'' *'' Linaria veratrifolia'' *'' Linaria verticillata'' *'' Linaria virgata'' *'' Linaria viscosa'' *'' Linaria volgensis'' *''

'' *'' Linaria warionis'' *'' Linaria weilleri'' *'' Linaria yunnanensis'' *'' Linaria yusufeliensis'' *'' Linaria × zaborskiana'' *'' Linaria zaissanica''

Etymology

The members of this genus are known in English as

toadflax Toadflax is the common name of several related genera of plants in the family Plantaginaceae, including: * '' Anarrhinum'' * ''Antirrhinum'', also called snapdragon * '' Chaenorhinum'', native to Turkey and the Mediterranean * '' Cymbalaria'' * ''L ...

, a name shared with several related genera. The 'toad' in toadflax may relate to the plants having historically been used to treat

bubonic plague Bubonic plague is one of three types of Plague (disease), plague caused by the Bacteria, bacterium ''Yersinia pestis''. One to seven days after exposure to the bacteria, flu-like symptoms develop. These symptoms include fever, headaches, and ...

, a false link having been drawn between the words 'bubo' and '

Bufo ''Bufo'' is a genus of true toads in the amphibian family Bufonidae. As traditionally defined, it was a wastebasket genus containing a large number of toads from much of the world but following taxonomic reviews most of these have been moved to ...

'. The scientific name ''Linaria'' means "resembling ''linum''" (

flax Flax, also known as common flax or linseed, is a flowering plant, ''Linum usitatissimum'', in the family Linaceae. It is cultivated as a food and fiber crop in regions of the world with temperate climates. In 2022, France produced 75% of t ...

), which the foliage of some species superficially resembles.

Distribution and habitat

The genus is native to temperate regions of Europe, northern Africa and Asia, with the highest species diversity in the Mediterranean region.

Ecology

Some ''Linaria'' are regarded as

noxious weed A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is harmful to agricultural or horticultural crops, natural habitats or ecosystems, or humans or lives ...

s. They are likely toxic to

livestock Livestock are the Domestication, domesticated animals that are raised in an Agriculture, agricultural setting to provide labour and produce diversified products for consumption such as meat, Egg as food, eggs, milk, fur, leather, and wool. The t ...

, but ruminants generally avoid them.Sing, S. E. and R. K. Peterson. (2011)
Assessing environmental risks for established invasive weeds: Dalmatian (''Linaria dalmatica'') and yellow (''L. vulgaris'') toadflax in North America.
''International Journal of Environmental Research and Public Health'' 8(7) 2828-53.

Chemical composition

''Linaria'' species are rich in

alkaloid Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large varie ...

iridoid Iridoids are a type of monoterpenoids in the general form of cyclopentanopyran, found in a wide variety of plants and some animals. They are biosynthetically derived from 8-oxogeranial. Iridoids are typically found in plants as glycosides, mo ...

terpene Terpenes () are a class of natural products consisting of compounds with the formula (C5H8)n for n ≥ 2. Terpenes are major biosynthetic building blocks. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predomi ...

phenolic acid Phenolic acids or phenolcarboxylic acids ? are phenolic compounds and types of aromatic acid compounds. Included in that class are substances containing a phenolic ring and an organic carboxylic acid function (C6-C1 skeleton). Two important nat ...

s and

flavonoid 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 ...

Vasicine Vasicine (peganine) is a quinazoline alkaloid. It is found in '' Justicia adhatoda'', after which it is named. It is additionally found in ''Peganum harmala''. Vasicine has been compared to theophylline both ''in vitro'' and ''in vivo''. It has ...

vasicinone Vasicinone is a quinazoline alkaloid. It shows bronchodilator action ''in vitro'' but bronchoconstrictor action ''in vivo''. Vasicinone was shown to have an antianaphylactic action. It has been found within ''Peganum harmala ''Peganum har ...

, 7-hyrdoxyvasicine, linarinic acid,

choline Choline is a cation with the chemical formula . Choline forms various Salt (chemistry), salts, such as choline chloride and choline bitartrate. An essential nutrient for animals, it is a structural component of phospholipids and cell membrane ...

, linavuline,

luteolin Luteolin is a flavone, a type of flavonoid, with a yellow crystalline appearance. Luteolin is the main yellow dye from the '' Reseda luteola'' plant, used for dyeing since at least the first millennium B.C. Luteolin was first isolated in pure f ...

, acacetin,

apigenin Apigenin (4′,5,7-trihydroxyflavone), found in many plants, is a flavone compound that is the aglycone of several naturally occurring glycosides. It is a yellow crystalline solid that has been used to dye wool. Apigenin is abundant in parsl ...

chrysin Chrysin, also called 5,7-dihydroxyflavone, is a flavone found in honey, propolis, the passion flowers, '' Passiflora caerulea'' and ''Passiflora incarnata'', and in '' Oroxylum indicum''. It is extracted from various plants, such as the blue passi ...

quercetin Quercetin is a plant flavonol from the flavonoid group of polyphenols. It is found in many fruits, vegetables, leaves, seeds, and grains; capers, red onions, and kale are common foods containing appreciable amounts of it. It has a bitter flavor ...

myricetin Myricetin is a member of the flavonoid class of polyphenolic compounds, with antioxidant properties. Common dietary sources include vegetables (including tomatoes), fruits (including oranges), nuts, berries, tea, and red wine. Myricetin is stru ...

, linarioside,

aucubin Aucubin is an iridoid glycoside. Iridoids are commonly found in plants and function as defensive compounds. Iridoids decrease the growth rates of many generalist herbivores. Natural occurrences Aucubin, as other Iridoid, iridoids, is found in ...

, linaride, iridolinaroside A-D, and iridolinarin A-C are some compounds found in plants of this genus.

Uses

Toadflaxes are used as food plants by the

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e of some

Lepidoptera Lepidoptera ( ) or lepidopterans is an order (biology), order of winged insects which includes butterflies and moths. About 180,000 species of the Lepidoptera have been described, representing 10% of the total described species of living organ ...

species, including the

mouse moth The mouse moth (''Amphipyra tragopoginis'') is a moth of the family Noctuidae. It is a widespread species with a Holarctic distribution. Distribution Europe (except the extreme north, and not occurring in the south of Spain, Sicily, or the Balka ...

(''Amphipyra tragopoginis'') and the

common buckeye ''Junonia coenia'', known as the common buckeye or buckeye, is a butterfly in the family Nymphalidae. Its range covers much of North America and some of Central America, including most of the eastern half of the US, the lower to middle Midwest, ...

(''Junonia coenia'').

Traditional medicine

''Linaria vulgaris'' has been used as a

medicinal herb Medicinal plants, also called medicinal herbs, have been discovered and used in traditional medicine practices since prehistoric times. Plants synthesize hundreds of chemical compounds for various functions, including Plant defense against h ...

.Duke, J. A
Ethnobotanical uses: ''Linaria vulgaris''.
Dr. Duke's Phytochemical and Ethnobotanical Databases.

References

Bibliography

* A Phylogeny of Toadflaxes (''Linaria'' Mill.) Based on Nuclear Internal Transcribed Spacer Sequences: Systematic and Evolutionary Consequences. Mario Fernández-Mazuecos, José Luis Blanco-Pastor, and Pablo Vargas. ''International Journal of Plant Sciences'', Vol. 174, No. 2 (February 2013), pp. 234–249 Published by: The University of Chicago Press, Article DOI: 10.1086/668790 * Vargas P, JA Rosselló, R Oyama, J Güemes. 2004 Molecular evidence for naturalness of genera in the tribe Antirrhineae (Scrophulariaceae) and three independent evolutionary lineages from the New World and the Old. ''Plant Systematics and Evolution'' 249:151–172. * {{Authority control Plantaginaceae genera Taxa named by Philip Miller