Overview

Comprehensive Description

Description

Perennial erect herbs. Leaves opposite below, alternate above. Flowers in terminal racemes. Calyx 5-lobed. Corolla strongly 2-lipped, variously coloured; tube gibbous at base; throat with a projecting palate, which closes the corolla mouth. Stamens 4. Capsule with 2 unequal cells
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© Mark Hyde, Bart Wursten and Petra Ballings

Source: Flora of Zimbabwe

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Distribution

Localities documented in Tropicos sources

Antirrhinum L.:
Honduras (Mesoamerica)
Mexico (Mesoamerica)
United States (North America)
Colombia (South America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.
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© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO 63110 USA

Source: Missouri Botanical Garden

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Ecology

Associations

Foodplant / pathogen
gregarious, subepidermal, fuscous-honey coloured pycnidium of Diplodina coelomycetous anamorph of Diplodina passerinii infects and damages stem (esp. base) of Antirrhinum
Remarks: season: 5-9

In Great Britain and/or Ireland:
Foodplant / parasite
Mortierella chlamydospora parasitises live root of Antirrhinum

Foodplant / pathogen
abundant, sessile sporodochium of Myrothecium dematiaceous anamorph of Myrothecium roridum infects and damages dry, brittle stem (base) of Antirrhinum
Other: minor host/prey

Foodplant / sap sucker
Myzus persicae sucks sap of Antirrhinum

Foodplant / feeds on
Phytonemus pallidus feeds on live Antirrhinum

Foodplant / pathogen
Rhodococcus fascians infects and damages non-flowering plant of Antirrhinum
Other: major host/prey

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Evolution and Systematics

Functional Adaptations

Functional adaptation

Bumblebees get a foothold: snapdragons
 

The petals of flowers attract pollinators by providing non-slip surfaces via conical epidermal cells.

   
  "Approximately 80% of angiosperms produce petals with similar conical epidermal cells (Kay et al. 1981), and numerous suggestions as to their function have been made. These include the possibilities that they enhance petal colour, act as a direct tactile cue, increase the temperature of the flower, influence scent production or release, or influence the wettability of the flower surface (Kay et al. 1981; Kevan and Lane 1985)." (Dyer et al. 2007:46)


"The plant surface is by default flat, and development away from this default is thought to have some function of evolutionary advantage. Although the functions of many plant epidermal cells have been described, the function of conical epidermal cells, a defining feature of petals in the majority of insect-pollinated flowers, has not. The location and frequency of conical cells have led to speculation that they play a role in attracting animal pollinators. Snapdragon (Antirrhinum) mutants lacking conical cells have been shown to be discriminated against by foraging bumblebees. Here we investigated the extent to which a difference in petal surface structure influences pollinator behavior through touch-based discrimination...We show that foraging bumblebees are able to discriminate between different surfaces via tactile cues alone. We find that bumblebees use color cues to discriminate against flowers that lack conical cells—but only when flower surfaces are presented at steep angles, making them difficult to manipulate. This facilitation of physical handling is a likely explanation for the prevalence of conical epidermal petal cells in most flowering plants." (Whitney et al. 2009:948)
  Learn more about this functional adaptation.
  • Dyer, A.G.; Whitney, H.M.; Arnold, S.E.J.; Glover, B. J.; Chittka, L. 2007. Mutations perturbing petal cell shape and anthocyanin synthesis influence bumblebee perception of Antirrhinum majus flower colour. Arthropod-Plant Interactions. 1: 45-55.
  • Whitney, HM: Chittka, L; Bruce, TJA; Glover, BJ. 2009. Conical epidermal cells allow bees to grip flowers and increase foraging efficiency. Current Biology. 19(11): 948-953.
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© The Biomimicry Institute

Source: AskNature

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Functional adaptation

Mutant gene flattens leaves: snapdragon
 

Mutant gene of snapdragons enhances photosynthesis by causing leaves to grow flat through uniform cell growth.

       
  Plants usually grow flat leaves to maximize the amount of sunlight they capture for photosynthesis. And now we know how. Unchecked, a leaf is more likely to be curved than flat. The leaf will buckle if cells near the edge grow more rapidly than cells near the center, and if the opposite happens the leaf becomes cup-shaped. Now it appears that the snapdragon uses a gene called CIN to ensure that cells in all regions of the leaf grow at a uniform rate, keeping the surface flat. (Courtesy of the Biomimicry Guild)
  Learn more about this functional adaptation.
  • Crawford, B. C. W.; Nath, U.; Carpenter, R.; Coen, E. S. 2004. Cincinnata controls both cell differentiation and growth in petal lobes and leaves of antirrhinum. Plant Physiology. 135(1): 244-253.
  • Nath, U; Crawford, BCW;Carpenter, R; Coen, E. 2003. Genetic control of surface curvature. Science. 299(5611): 1404-1407.
  • Coen, E. 2003. Way to grow. New Scientist. 8 November: 44-47.
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Wikipedia

Antirrhinum

Antirrhinum is a genus of plants commonly known as snapdragons or dragon flowers, from the flowers' fancied resemblance to the face of a dragon that opens and closes its mouth when laterally squeezed. They are native to rocky areas of Europe, the United States, and North Africa.[1]

Etymology[edit]

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"; thus, "like a nose", possibly referring to the nose-like capsule in its mature state.[2]

Taxonomy[edit]

Antirrhinum used to be treated within the family Scrophulariaceae, but studies of DNA sequences have led to its inclusion in a vastly enlarged family Plantaginaceae. The taxonomy of this genus is unresolved at present. At one extreme, the USDA Plants Database recognises only the Old World species of sect. Antirrhinum in the genus, listing only A. majus (the garden snapdragon, the only species in the section naturalised in North America).[3] 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, provided that one species (A. cyathiferum) 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:

The Garden Snapdragon is an important garden plant; cultivars of this species have showy white, crimson, or yellow bilabiate flowers. It is also important as a model organism in botanical research, and its genome 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[edit]

Snapdragons are often considered as cold-season annual plants and do best in full or partial sun, in well drained soil (although they do require regular watering[4]). They are classified commercially as a range of heights: dwarf (6-8 inches), medium (15-30 inches) and tall (30-48 inches).

Genetic studies[edit]

Snapdragon is a typical example of incomplete dominance by the red allele with the anthocyanin pigment. Any cross between red-flowered and white-flowered snapdragons, give an intermediate and heterozygous phenotype with pink flowers, that carries both the dominant and recessive alleles.[5]

Several species of Antirrhinum are self-incompatible, meaning that a plant cannot be fertilised by its own pollen.[6] Self-incompatibility in the genus has been studied since the early 1900s.[6] Self-incompatibility in Antirrhinum species is controlled gametophytically and shares many important features with self-incompatibility systems in Rosaceae and Solanaceae.[7]

Gallery[edit]

Notes[edit]

  1. ^ RHS A-Z encyclopedia of garden plants. United Kingdom: Dorling Kindersley. 2008. p. 1136. ISBN 1405332964. 
  2. ^ "Antirrhinum orontium, Misopates orontium, Small Snapdragon, לוע-ארי קטן". Flowersinisrael.com. Retrieved 2011-07-15. 
  3. ^ http://plants.usda.gov/java/profile?symbol=ANTIR2
  4. ^ http://www.sunset.com/garden/flowers-plants/snapdragon-antirrhinum-majus-00400000020410/
  5. ^ Hartl, Daniel L.; Elizabeth W. Jones (2005). Genetics : analysis of genes and genomes (sixth edition). Jones & Bartlett publishers. pp. 3.6 Incomplete Dominance and Epistasis. ISBN 0-7637-1511-5. 
  6. ^ a b Xue, Yongbiao; Rosemary Carpenter, Hugh G. Dickinson, Enrico S. Coen (May 1996). "Origin of allelic diversity in antirrhinum S locus RNases". The Plant Cell (American Society of Plant Physiologists) 8 (5): 805–814. doi:10.2307/3870283. JSTOR 3870283. PMC 161139. PMID 8672882. 
  7. ^ Takayama, Seiji; Akira Isogai (2005). "Self-incompatibility in plants". Annual Review of Plant Biology (Annual Reviews) 56: 467–489. doi:10.1146/annurev.arplant.56.032604.144249. PMID 15862104. 

Sources[edit]


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