Antirrhinum

Antirrhinum

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Encyclopedia
Antirrhinum is a genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

s commonly known as snapdragons from the flowers' fancied resemblance to the face of a dragon
European dragon
European dragons are legendary creatures in folklore and mythology among the overlapping cultures of Europe.In European folklore, a dragon is a serpentine legendary creature. The Latin word draco, as in constellation Draco, comes directly from Greek δράκων,...

 that opens and closes its mouth when laterally squeezed (thus the 'snap'). The antirrhinums used to be treated as the family Scrophulariaceae
Scrophulariaceae
Scrophulariaceae, the figwort family, are a family of flowering plants. The plants are annual or perennial herbs with flowers with bilateral or rarely radial symmetry. Members of the Scrophulariaceae have a cosmopolitan distribution, with the majority found in temperate areas, including...

, but studies of DNA sequences have led to the inclusion of Antirrhinum in a vastly enlarged family Plantaginaceae
Plantaginaceae
Plantaginaceae Juss. or plantain family, are a family of flowering plants in the order Lamiales. The type genus is Plantago L..In older classifications it used to be the only family of the order Plantaginales, but numerous phylogenetic studies, summarized by the Angiosperm Phylogeny Group, have...

. The word "Antirrhinum" is derived from αντίρῥῑνόν "antirrhinon" which in turn was derived from Greek anti (αντί), "like," and rhis (ῥίς, ινοϛ), "nose", inus (-ινοϛ), "of" or "pertaining to". The name literally means "like a nose" in Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 and probably refers to the nose-like capsule in its mature state.

Taxonomy


The taxonomy of this genus is disputed at present. At one extreme, the USDA PLANTS database recognises only the Old World
Old World
The Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....

 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of sect. Antirrhinum in the genus, listing only the Garden Snapdragon A. majus (the only species in the section naturalised in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

). At the other, Thompson (1988) places 36 species in the genus; many modern botanists accept this circumscription. New species also continue to be discovered (see e.g. Romo et al., 1995).

Recent research in the molecular systematics of this group, and related species, by Oyama and Baum (2004), has confirmed that the genus as described by Thompson is monophyletic
Monophyly
In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...

, provided that one species (A. cyathiferum
Antirrhinum cyathiferum
Antirrhinum cyathiferum is a species of New World snapdragon known by the common names dog's mouth and Deep Canyon snapdragon. It is native to the deserts of northern Mexico and adjacent California and Arizona. This is an annual herb producing a hairy, erect, non-climbing stem with many...

) is removed to a separate genus, and two others (previously listed as Mohavea confertiflora and M. breviflora) are included. The species list at the right follows these conclusions. It is widely agreed that this broad group should be subdivided into three or four subgroups, but the level at which this should be done, and exactly which species should be grouped together, remain unclear. Some authors continue to follow Thompson in using a large genus Antirrhinum, which is then divided into several sections; others treat Thompson's genus as a tribe or subtribe, and divide it into several genera.

If the broad circumscription is accepted, its sections are as follows:
  • Section Antirrhinum: about 20 Old World species of perennial plant
    Perennial plant
    A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...

    s, the type Antirrhinum majus, mostly native to the western Mediterranean region with a focus on the Iberian Peninsula
    Iberian Peninsula
    The Iberian Peninsula , sometimes called Iberia, is located in the extreme southwest of Europe and includes the modern-day sovereign states of Spain, Portugal and Andorra, as well as the British Overseas Territory of Gibraltar...

    .
  • Section Orontium: two to six species, also Mediterranean. The species in this section, including the type Lesser Snapdragon A. orontium, are often treated in the genus Misopates.
  • Section Saerorhinum: about 16 New World
    New World
    The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...

     species, mostly annual plant
    Annual plant
    An annual plant is a plant that usually germinates, flowers, and dies in a year or season. True annuals will only live longer than a year if they are prevented from setting seed...

    s and mostly native to California
    California
    California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

    , though species are found from Oregon
    Oregon
    Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

     to Baja California Sur
    Baja California Sur
    Baja California Sur , is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. Before becoming a state on October 8, 1974, the area was known as the South Territory of Baja California. It has an area of , or 3.57% of the land mass of Mexico and comprises...

     and as far east as Utah
    Utah
    Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...

    . Like other authors, Thompson placed A. cyathiferum in this section, but Oyama and Baum, following earlier authors, suggest that it should be reclassified in genus Pseudorontium, while Mohavea confertiflora and M. breviflora should be included. Some authors classify the species in this section into the genera Sairocarpus, Howelliella and Neogaerrhinum.


The Garden Snapdragon is an important garden plant; cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...

s of this species have showy white, crimson, or yellow bilabiate flowers. It is also important as a model organism
Model organism
A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms. Model organisms are in vivo models and are widely used to...

 in botanical research, and its genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....

 has been studied in detail.

While Antirrhinum majus is the plant that is usually meant of the word "snapdragon" if used on its own, many other species in the genus, and in the family Scrophulariaceae more widely, have common names that include the word "snapdragon".

Growth


Snapdragons are perennial plant
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...

s often sold as cold-season annual plant
Annual plant
An annual plant is a plant that usually germinates, flowers, and dies in a year or season. True annuals will only live longer than a year if they are prevented from setting seed...

s and do best in full or partial sun. They are available in a range of heights: dwarf (6-8 inches), medium (15-30 inches) and tall (30-48 inches). Plant them in a soil that drains well to prevent the roots from rotting.

Genetic studies


Snapdragon is a typical example of incomplete dominance by the red allele
Allele
An allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation...

 with the anthocyanin
Anthocyanin
Anthocyanins are water-soluble vacuolar pigments that may appear red, purple, or blue according to pH...

 pigment. Any cross between red-flowered and white-flowered snapdragons, give an intermediate and heterozygous phenotype
Phenotype
A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...

 with pink flowers, that carries both the dominant and recessive alleles.

Several species of Antirrhinum are self-incompatible
Self-incompatibility in plants
Self-incompatibility is a general name for several genetic mechanisms in angiosperms, which prevent self-fertilization and thus encourage outcrossing...

, meaning that a plant cannot be fertilised by its own pollen. Self-incompatibility in the genus has been studied since the early 1900s. Self-incompatibility in Antirrhinum species is controlled gametophytically and shares many important features with self-incompatibility systems in Rosaceae
Rosaceae
Rosaceae are a medium-sized family of flowering plants, including about 2830 species in 95 genera. The name is derived from the type genus Rosa. Among the largest genera are Alchemilla , Sorbus , Crataegus , Cotoneaster , and Rubus...

 and Solanaceae
Solanaceae
Solanaceae are a family of flowering plants that include a number of important agricultural crops as well as many toxic plants. The name of the family comes from the Latin Solanum "the nightshade plant", but the further etymology of that word is unclear...

.

Sources

  • Thompson, D. M. (1988). Systematics of Antirrhinum (Scrophulariaceae) in the New World. Systematic Botany Monographs 22.

External links