Antirrhinum is a genus of flowering plants in the family Plantaginaceae (order Lamiales), commonly known as snapdragons or dragon flowers. The common names arise from the flowers' fancied resemblance to a dragon's face that opens and closes its mouth when the sides of the bloom are gently squeezed — a trait long delightful to children and gardeners alike. The genus is also occasionally called toadflax or dog flower.
The genus is characterised by personate bilabiate flowers with an inferior gibbous corolla — a distinctive two-lipped, closed-mouth form. Plants range in habit from dwarf cultivars of 15–20 cm to tall selections reaching 120 cm. Though botanically short-lived perennials, they are frequently grown as annuals and are commercially classed as midget/dwarf, medium, or tall according to height. Flower colours span white, yellow, orange, red, purple, and pink, including many multicoloured patterns.
In its natural range Antirrhinum is found on rocky outcrops and walls across Europe, North Africa, the United States, and Canada. The genus was formerly placed in Scrophulariaceae, but DNA sequence studies led to its transfer into the enlarged Plantaginaceae within tribe Antirrhineae. Antirrhinum majus in particular has become an important model organism in botanical genetics, and its genome has been studied in detail.
Beyond ornamental use, the genus has practical applications: seeds yield edible oils (historically pressed in Russia), flowers and leaves have been applied in anti-inflammatory poultices, and a green dye can be extracted from the flowers.
Etymology
The genus name Antirrhinum derives from the Greek ἀντίρρινον (antirrhinon), itself composed of ἀντί (anti, "opposite" or "counterfeiting") and ῥίς (rhis, genitive ῥινός rhinos, "nose"). The name alludes to the flower's resemblance to an animal's snout or mouth. The common name "snapdragon" reflects the same observation — the bilabiate corolla snaps open and shut like a dragon's jaw when squeezed laterally.
Distribution
Antirrhinum species are native to rocky habitats across Europe, North Africa, the United States, and Canada. Within Europe the genus reaches its greatest diversity in the Iberian Peninsula and Mediterranean region. Species are widely naturalised beyond their native range through cultivation.
Ecology
Snapdragons are short-lived perennials that perform best in full or partial sun in well-drained soil; their roots are susceptible to rotting with excess moisture, though regular watering is required. They bloom primarily from April to June and from August to October in the Northern Hemisphere. Plants are sensitive to ethylene gas — removing spent flowers (deadheading) both prolongs blooming and reduces ethylene exposure from decaying tissue or nearby ripening fruit. The genus shows notable ecological diversity, particularly among New World species (sometimes segregated as Saerorhinum).
Cultivation
The snapdragon is one of the most widely grown cool-season ornamentals globally, cultivated from temperate to tropical zones as a bedding plant, rockery subject, herbaceous border specimen, and container plant. Commercially, plants are selected across three height classes — dwarf (15–20 cm), medium (40–75 cm), and tall (75–120 cm) — to suit different garden contexts. Cut-flower production is also significant. Beyond horticulture, Antirrhinum majus is an established model organism in plant biology; its genome has been sequenced and studied in depth, yielding insights into flower symmetry and developmental genetics.
Cultural Uses
Antirrhinum has modest but longstanding non-ornamental uses. The seeds contain edible oils that have been pressed and used in cooking, particularly in Russia. Flowers and leaves have traditionally been applied as poultices for their reputed anti-inflammatory properties. A green dye can also be obtained from the flowers.
Taxonomy Notes
Antirrhinum was historically placed in Scrophulariaceae, a large family of figworts. Molecular phylogenetic studies based on DNA sequences demonstrated that Scrophulariaceae as traditionally circumscribed was polyphyletic, leading to a major reorganisation; Antirrhinum and many allied genera were transferred to an enlarged Plantaginaceae within the tribe Antirrhineae. GBIF recognises the genus at family Plantaginaceae, order Lamiales.
