Antirrhinum majus

Species of flowering plant

Antirrhinum majus, the common snapdragon (often especially in horticulture simply "snapdragon"), is a species of flowering plant belonging to the genus Antirrhinum. The plant was placed in the family Plantaginaceae following a revision of its prior classical family, Scrophulariaceae. The common name "snapdragon", originates from the flowers' reaction to having their throats squeezed, which causes the "mouth" of the flower to snap open like a dragon's mouth. It is widely used as an ornamental plant in borders and as a cut flower. It is perennial but usually cultivated as an annual plant. The species has been in culture since the 15th century.

It is an herbaceous perennial plant, growing to 0.5–1 m tall, rarely up to 2 m. The leaves are spirally arranged, broadly lanceolate, 1–7 cm long and 2–2.5 cm broad. The upper glandular stalk is stalk round, sometimes woody to the middle. The opposite leaves are simple, elliptic or ovate to broad lanceolate, sometimes linear and usually bleak. Leaflets are missing. The flowers are produced on a tall spike, each flower is 3.5 4.5 cm long, zygomorphic, with two 'lips' closing the corolla tube lobed divided into three parts and is purple red, almost 5 cm long. Wild plants have pink to purple flowers, often with yellow lips. Most 8 to 30 short stalked flowers are in an inflorescence together; the inflorescence axis is glandular hairy. The crown is 25 to 45 (rarely to 70) millimeters long and in different colors (red, pink, orange, yellow, white). The "maw" of the crown is closed by protuberance of the lower lip, one speaks here of "masked", and everted baggy at the bottom. There is a circle with four stamens. The plants are pollinated by bumblebees, who are strong enough to gently and briefly open male flowers to enter and exit them without difficulty, collecting pollen in the process. A snapdragon's calyx is up to 8 mm long, with sepals of equal length, oblong to broad. The ovary is supreme. The fruit is an ovoid capsule 10–14 mm diameter shaped like a skull, containing numerous small seeds.

Antirrhinin is an anthocyanin found in A. majus. It is the 3 rutinoside of cyanidin. Its active ingredients include mucilages, gallic acid, resins, pectin and bitters. It is a topical emollient, antiphlogistic, astringent, antiscorbutic, hepatic and diuretic. It is effective against inflammations, it is used for haemorrhoids. It has been used in gargles against ulcerations of the oral cavity. Internally, it can be used for colitis and heartburn. Externally, as poultices, on erythemas.

It is native to from southern central France, and the eastern Pyrenees to north eastern Spain and the Balearic Islands. They often grow in crevices and walls.

Antirrhinum majus may suffer from some pests and diseases.

In the laboratory it is a model organism, for example containing the gene DEFICIENS which provides the letter "D" in the acronym MADS box for a family of genes which are important in plant development. Antirrhinum majus has been used as a model organism in biochemical and developmental genetics for nearly a century. Many of the characteristics of A. majus made it desirable as a model organism; these include its diploid inheritance, ease of cultivation (having a relatively short generation time of around 4 months), its ease of both self pollination and cross pollination, and A. majus's variation in morphology and flowering color. It also benefits from its divergence from Arabidopsis thaliana, with A. thaliana's use as a common eudicot model, it has been used to compare against A. majus in developmental studies. It was shown that low temperature dependent transposition was the cause of the methylation/demethylation of Tam3, not the other way around as previously believed. It was shown in a study that decreases in the methylation of Tam3 were found in tissue that was still developing at cooler temperatures, but not in tissue that was developed or grown in hotter temperatures. Antirrhinum majus has also been used to examine the relationship between pollinators and plants. With debate as to the evolutionary advantages the conical papillate shape of flower petals, with arguments suggesting the shape either enhanced and intensified the color of the flower or aided in orienting pollinators through sight or touch. The benefit that A. majus brought was through an identification of a mutation at the MIXTA locus that prevented this conical petal shape from forming. This allowed testing of the pollination plants with and without conical petals as well as comparisons of the absorption of light between these two groups. With the MIXTA gene being necessary in the formation of conical cells, the use of the gene in breeding of Antirrhinum was crucial, and allowed for the tests which showed why many plants produced conical papillate epidermal cells. Another role A. majus played in examining the relationship between pollinator and plant were in the studies of floral scents. Two of A. majus's enzymes, phenylpropanoids and isoprenoids, were used in the study of its floral scent production and the scent's effect on attracting pollinators.