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Verbascum thapsus

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Verbascum thapsus
File:Starr 040723 0030 verbascum thapsus.jpg
Verbascum thapsus in Hawaii
Secure
Scientific classification
Kingdom:
Plantae
Division:
Magnoliophyta
Class:
Magnoliopsida
Order:
Lamiales
Family:
Scrophulariaceae
Genus:
Verbascum
Species:
V. thapsus
Binomial name
Verbascum thapsus

Verbascum thapsus (Common or Great Mullein) is a species of mullein, native to Europe, northern Africa and Asia, and introduced in the Americas and Australia. Other common names include Woolly or Flannel Mullein, Shepherd's Club, and Aaron's Rod. The specific epithet thapsus was first used by Theophrastus for an unspecified herb from the Ancient Greek settlement of Thapsos, near modern Syracuse, Sicily,[1] though it is frequently related to the ancient Tunisian city of Thapsus.[2]

Common mullein is a hairy biennial plant that can grow up to 2 meters. Its small, yellow flowers are densely grouped on the stem, which bolts from a large rosette of leaves. It grows in a wide variety of habitats, but favors well-lit disturbed soils the most, which it can invades rapidly thanks to its long-lived seeds. Common Mullein is a weedy, but rarely competitive species. While not an issue for most cultures, it hosts many insects that can be harmful to other plants, such as the tarnished plant bug, and although individuals are easy to destroy by hand, it is difficult to destroy a population permanently.

V. thapsus is widely used as an herbal remedy with emollient and astringent. It is especially recommended for coughs and related problems, but also used in topical applications against a variety of skin problems. The plant was also used to make dyes and torches.

Morphology

File:Starr 040723 0260 verbascum thapsus.jpg
A stem-less rosette in Hawaii

V. thapsus is a dicotyledonous biennial plant that produces only a rosette of leaves in the first year. In the second year it produces a tall stem 1–2 m tall (stems reaching to 3 m have been reported) with a dense spike of flowers on the upper half of the stem, only a few of which flower at the same time. All parts of the plant are covered with dense, silvery and star-shaped trichomes. The stem, nearly an inch across, is solid, and is usually unbranched, rarely branched below the inflorescence, and typically doing so when damaged. Dry stems and seed capsules usually persist in winter. The plants produces shallow taproots.[3][4][5][6][7]

The leaves are alternate, thick and decurrent, varying between oblong and oblanceolate. The basal rosette leaves are the largest, up to 50 cm long and 14 cm broad, with steadily smaller leaves higher on the flowering stem.[3][8][6][9]

File:Starr 040723 0267 verbascum thapsus.jpg
A closeup of the flowers

V. thapsus flowers are pentamerous, with a 5-lobed calyx tube and a yellow corolla 12–35 mm wide, and five stamens. The three upper stamens are longer, with their filaments covered with yellow or whitish hair, while the two other stamen have glabrous filaments. Flowering occurs throughout the summer. The flowers are almost sessile, with only very short pedicels (1–3 mm). The fruit is an ovoid 3–10 mm long capsule containing large numbers of minute (less than a millimetre) brown seeds.[3][8][6][9]

There are three subspecies:[10]

  • Verbascum thapsus subsp. thapsus; widespread.
  • Verbascum thapsus subsp. crassifolium (Lam.) Murb.; Mediterranean region.
  • Verbascum thapsus subsp. giganteum (Willk.) Nyman; Spain, endemic.

Distribution and naturalization

The species has a wide native range including Europe, northern Africa and Asia, from the Azores and Canary Islands east to western China, north to the British Isles, Scandinavia and Siberia, and south to the Himalaya.[10][4][11] It has been introduced throughout the temperate world, and is naturalised in North America (including Hawaii), Australia, Chile, Hispaniola and Argentina (1925).[11][12][13] In the United States it was imported very early and cultivated for its medicinal property. By the 1630s, it was already escaped and had begun spreading so much that Amos Eaton thought it was a native plant, and gives it as such in 1818.[14] In 1839 it is already reported in Michigan and in 1876, in California.[15] It is now found commonly in all the states,[16] and all the Canadian provinces.[17]

Ecological aspects

Common Mullein is most frequent met as a colonizer of bare and disturbed soil. This is in part due to its intolerance of shade and the very long periods during which the seeds can remain dormant before germination. It is not an agricultural weed, although its presence can be very difficult to completely eradicate, and is especially problematic in overgrazed pastures.[9][15][18]

File:Starr 040723 0074 verbascum thapsus.jpg
V. thapsus grows best where there is little competition

V. thapsus favors dry, sandy or gravelly soils, although it can grow in a variety of habitats: meadows, roadsides, forest clearings and pastures. It germinates almost solely in bare soil, at temperatures between 10 °C and 40 °C.[9] This ability to grow in a wide range of habitats has been linked to strong phenotype variation rather than adaptation capacities.[19] While it can germinate in total darkness if proper conditions are present (tests give a 35% germination rate under ideal conditions), in nature, it will only appear if the seeds are exposed, or very close to the soil surface. While it can also appear in areas where some vegetation exist, growth of the rosettes on bare soil is four to seven times more rapid.[9]

Megachilidae bees, notably Anthidium species, use the hair in making their nests.[20] Seeds are generally too small for birds to feed on,[20] although the American Goldfinch was reported to consume them.[21] Other bird species have been reported to consume the leaves (Hawaiian Goose)[22] or flowers (Palila)[23] of V. thapsus, or to use the plant as a source when foraging for insects (White-headed Woodpecker).[24]

The species is considered a noxious weed in Colorado (Class C),[25] Hawaii[26] and Victoria, Australia (regionally prohibited in the West Gippsland region, and regionally controlled in several others).[27]

Life cycle

Common Mullein requires vernalization before it can flowers, which is the reason why it is a biennial.[9] This vernalization is linked to starch degradation in the root activated by low temperatures, and gibberellin application bypasses this requirement.[28] Plants that germinate in autumn overwinter if they are large enough (rosettes less than 15 cm across die in winter) before flowering the next year. The entire plant usually dies at the end of its second year.[9] Some individuals, especially in the northern parts of the species' range, flower in their third year. Under better conditions, some individual flower in the first year.[29] Triennial individuals were found to produce less seeds than biennial and annual ones. While year of flowering and size are linked to the environment, most other characteristics appear to be genetic.[30]

A given flower is open only for a single day. Flowers are autogamous and will self-pollinate if they have not been pollinated by insects during the day. While many insects visit the flowers, only some bees actually accomplish pollination.[9][15][18] Visitors include halictid bees and hoverflies.[20]

Seeds of V. thapsus maintain their germinative powers for decades, up to a hundred years, according to some studies.[31] Because of this, and because the plant is an extremely prolific seed bearer (up to 180,000[15][9] or 240,000[18]), it remains in the soil seed bank for extended periods of time, and can sprout from apparently bare ground,[9] or shortly after forest fires[18] long after previous plants have died. Common Mullein rarely establishes on new grounds without human intervention because its seeds are not dispersed very far. Seed dispersion requires the stem to be moved by wind or animal movement; 75% of the seeds fall within a meter of the parent plant, and 93% fall within five meters.[9]

Agricultural impacts and control

Common Mullein is not considered an agricultural weed because it cannot compete with established plants, and is easily crowded out by them, except in areas where vegetation is sparse to begin with, such as Californian semi-desertic areas (Eastern Sierra Nevada), where it crowds out native herbs and grasses. Its tendency to appear after forest fires also disturbs the normal ecological succession.[9][18]

Despite not being an agricultural weed in itself, it hosts a number of insects and diseases, including both pests and beneficial insects.[32] It is also a potential reservoir of the Cucumber mosaic virus.[33] A study found V. thapsus hosts insects from 29 different families. Most of the pests found were western flower thrips (Frankliniella occidentalis), Lygus species, such as the tarnished plant bug (L. lineolaris), and various spider mites from the family Tetranychidae. These make the plant a potential reservoir for overwintering pests.[32]

Other insects commonly found on Common Mullein feeds on Verbascum species in general. They include mullein thrips (Haplothrips verbasci),[32] Gymnaetron tetrum and the Mullein Moth (Cucullia verbasci).[15] Useful insects are also hosted by Common Mullein, including predatory mites of the Galendromus, Typhlodromus and Amblyseius genera (Phytoseiidae), the minute pirate bug (Orius tristicolor)[32] and the mullein plant bug (Campylomma verbasci).[34] The plant's ability to host both pests and beneficials makes it potentially useful to help stabilize populations of insects used for biological control in other cultures, like Campylomma verbasci and Dicyphus hesperus (Miridae), a predator of whiteflies.[35] A number of Lepidoptera species, including the Stalk borer (Papaipema nebris) and Gray Hairstreak (Strymon melinus), also use V. thapsus as a host plant.[36]

The hairy leaves are resistant to grazing and contact herbicides.

Control of the plant, when desired, is best managed via mechanical means, such as hand pulling and hoeing, preferably followed by sowing of native plants. Animals rarely graze it because of its irritating hairs, and liquid herbicides require surfactants to be effective, as the hair causes water to roll off the plant, much like the lotus effect. Burning is ineffective, as it only creates new bare areas for seedlings to colonize.[9][15][18] G. tetrum and Cucullia verbasci usually have little effect on V. thapsus populations.[15] Goats and chickens have been proposed to control Mullein.[9] Effective (when used with a surfactant) contact herbicides include glyphosate,[15][18] triclopyr[15] and sulfurometuron-methyl.[18] Ground herbicides, like tebuthiuron, are also effective, but recreate bare ground and require repeated application to prevent regrowth.[9]

Uses

Great Mullein has been used since ancient times as a remedy for skin, throat and breathing ailments. It has long had a medicinal reputation, especially as an astringent and emollient. It contains mucilage, several saponins, coumarin and glycosides. Dioscorides recommended it for diseases of the lung and it is nowadays widely available in health and herbal stores. Non-medical uses have included dyeing and making torches.

Medical use

Dioscorides first recommended the plant 2000 years ago, against pulmonary diseases,[37] and this has remained one of its primary uses, especially against cough. Leaf decoctions or herbal teas were used for expectoration, consumption, dry cough, bronchitis, sore throat and hemorrhoids. Leaves were also smoked against pulmonary ailments, a tradition that was rapidly transmitted to Native American peoples.[38][39] Natives also used the plants to make syrups and against croup.[28] The combination of expectorant saponins and emollient mucilage makes the plant particularly effective at this for cough.[28] All preparations meant to be drunk have to be finely filtered to eliminate the irritating hairs.[28]

Oil from the flowers was used against catarrhs, colics and, in Germany, earaches, frostbite, eczema and other external conditions.[38] Topical application of various mullein-based preparations was recommended for the treatment of warts,[40] boils, carbuncles, hemorrhoids, and chilblains, amongst others.[38][39] Recent studies have found that Mullein (especially the flowers) contains glycyrrhizin compounds with bactericide and potential anti-tumoral action.[41] Different extracts have varying levels of efficiency against bacterias.[28] In Germany, a governmental commission sanctioned medicinal use of the plant for catarrhs.[42] It was also part of the National Formulary in the United States[39] and United Kingdom.[38] The plant's leaves, in addition to the seeds, have been reported to contain rotenone, although quantities are unknown.[43]

In Spanish, Great Mullein is called Gordolobo, a name transferred to Gnaphalium conoideum. G. conoideum is used similarly by the Mexican Aztecs, which caused confusion in naming, and the two are sold under the name "Gordolobo," which has lead to at least one case of poisoning due to confusion of G. conoideum with Senecio longilobus.[44]

Other uses

Like many ancient plants (Pliny the Elder describes it in his Naturalis Historia),[45] Common Mullein was linked to witches,[38] although the relationship remained generally ambiguous, and the plant was also widely held to ward off curses and evil spirits.[38][39][37][28] The seeds contain several compounds (saponins, glycosides, coumarin, rotenone) that cause breathing problems in fish, and have been widely used for fishing.[15][46]

The flowers provide dyes of bright yellow or green, and have been used for hair coloring.[38][43] The dried leaves and hair were made into candle wicks, or put into shoes to help with insulating them. The dried stems were also dipped into suet or wax to make torches.[38][39]

References

  1. ^ Template:Sv icon Den virtuella Floran: Verbascum thapsus, retrieved on December 29 2006.
  2. ^ Charters, Michael L. "Plant name: T". California Plant Names: Latin and Greek Meanings and Derivations. Calflora.net. Retrieved 2006-12-06.
  3. ^ a b c Blamey, M. & Grey-Wilson, C. (1989). Flora of Britain and Northern Europe. Hodder & Stoughton. ISBN 0-340-40170-2
  4. ^ a b "Verbascum thapsus". Flora of China. eFloras.org. Retrieved 2006-11-29.
  5. ^ Purple Sage Herbs: Verbascum thapsus, retrieved on December 29 2006.
  6. ^ a b c Plants of British Columbia: Verbascum thapsus, retrieved on December 29 2006.
  7. ^ Wetherwax, M. (1993). "Verbascum thapsus L." Jepson Manual online. University of California at Berkeley. Retrieved 2006-12-06.
  8. ^ a b Huxley, A., ed. (1992). New RHS Dictionary of Gardening. Macmillan. ISBN 0-333-47494-5
  9. ^ a b c d e f g h i j k l m n o Hoshovsky, Marc C. (2001). "Element Stewardship Abstract for Verbascum thapsus" (PDF). The Global Invasive Species Initiative. Retrieved 2006-11-29. {{cite web}}: Unknown parameter |month= ignored (help) Cite error: The named reference "Hoshovsky" was defined multiple times with different content (see the help page).
  10. ^ a b Flora Europaea: Verbascum thapsus, retrieved on December 29 2006.
  11. ^ a b Germplasm Resources Information Network: Verbascum thapsus, retrieved on December 29 2006.
  12. ^ Template:Es icon "Ficha de la Especie Verbascum thapsus". Base de Datos sobre Invasiones Biológicas en Argentina. Universidad Nacional del Sur. Retrieved 2006-12-06.
  13. ^ "Verbascum thapsus". Global Invasive Species Database. IUCN Invasive Species Specialist Group. 8 July 2005. Retrieved 2006-11-29. {{cite web}}: Check date values in: |date= (help)
  14. ^ Mitch, Larry W. "Common Mullein—the Roadside Torch Parade". Intriguing World of Weeds. Weed Science Society of America. Retrieved 2006-12-06.
  15. ^ a b c d e f g h i j Remaley, Tom (1998). "Verbascum thapsus". Plant Conservation Alliance's Alien Plant Working Group. Retrieved 2006-11-29.
  16. ^ "Verbascum thapsus". PLANTS Database. USDA Natural Resources Conservation Service. Retrieved 2006-12-06.
  17. ^ NatureServe Explorer: Verbascum thapsus, retrieved December 29 2006.
  18. ^ a b c d e f g h Pitcairn, Michael. "Verbascum thapsus". University of California Davis. Retrieved 2006-12-06. Cite error: The named reference "davis" was defined multiple times with different content (see the help page).
  19. ^ Parker, Ingrid M. (2003). "An Evolutionary Approach to Understanding the Biology of Invasions: Local Adaptation and General-Purpose Genotypes in the Weed Verbascum thapsus". Conservation Biology. 17 (1): 59–72. doi:10.1046/j.1523-1739.2003.02019.x. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  20. ^ a b c Hilty, John. "Great Mullein". Weedy Wildflowers of Illinois. Illinois Wildflowers. Retrieved 2006-12-06. Cite error: The named reference "illinois" was defined multiple times with different content (see the help page).
  21. ^ Coutlee, Ellen L. (1963). "Maintenance Behavior of the American Goldfinch" (PDF). Wilson Bulletin. pp. 342–357. ISSN 0043-5643. {{cite web}}: Unknown parameter |month= ignored (help)
  22. ^ Banko et als (1999). "Hawaiian Goose (Nene) (Branta sandvicensis): Food Habits". The Birds of North America, No. 434. The Birds of North America Online. Retrieved 2006-12-17.
  23. ^ Banko et als (2002). "Palila (Loxioides bailleui): Food Habits". The Birds of North America, No. 679. Retrieved 2006-12-17.
  24. ^ Garrett et als (1996). "White-headed Woodpecker (Picoides albolarvatus): Food Habits". The Birds of North America, No. 252. Retrieved 2006-12-17.
  25. ^ "Colorado State-listed Noxious Weeds". PLANTS Database. USDA Natural Resources Conservation Service. Retrieved 2006-12-06.
  26. ^ "Hawaii State-listed Noxious Weeds". PLANTS Database. USDA Natural Resources Conservation Service. Retrieved 2006-12-06.
  27. ^ Faithful, Ian. "Great mullein". Victoria Department of Primary Industries. Retrieved 2006-12-06.
  28. ^ a b c d e f Turker, Arzu Ucar (2005). "Common Mullein (Verbascum thapsus L.): Recent Advances in Research". Phytotherapy Research. 19 (9): 733–739. doi:10.1002/ptr.1653. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  29. ^ Reinartz, James A. (1984). "Life History Variation of Common Mullein (Verbascum Thapsus): I. Latitudinal Differences in Population Dynamics and Timing of Reproduction". The Journal of Ecology. 72 (3): 897–912. ISSN 0022-0477. {{cite journal}}: Unknown parameter |month= ignored (help)
  30. ^ Reinartz, James A. (1984). "Life History Variation of Common Mullein (Verbascum Thapsus): III. Differences Among Sequential Cohorts". The Journal of Ecology. 72 (3): 927–936. {{cite journal}}: Unknown parameter |month= ignored (help)
  31. ^ Kivilaan, A. (1981). "The One Hundred-Year Period for Dr. Beal's Seed Viability Experiment". American Journal of Botany. 69 (9): 1290–1292. ISSN 0002-9122. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  32. ^ a b c d Horton, David R. (2003). "Numbers and types of arthropods overwintering on common mullein, Verbascum thapsus L. (Scrophulariaceae), in a central Washington fruit-growing region" (PDF). Journal of the Entomological Society of British Columbia. 100: 79–86. ISSN 0071-0733. Retrieved 2006-11-30. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  33. ^ Price, W. C. (1940). "Comparative Host Ranges of Six Plant Viruses". American Journal of Botany. 57 (7): 530–541. ISSN 00029122 Parameter error in {{issn}}: Invalid ISSN.. {{cite journal}}: Unknown parameter |month= ignored (help)
  34. ^ Higbee, Bradley S. "Campylomma verbasci (Meyer)". Biological Control: A Guide to Natural Enemies in North America. Cornell University. Retrieved 2006-12-06.
  35. ^ Sanchez, Juan Antonio (2003). "The effects of mullein plants (Verbascum thapsus) on the population dynamics of Dicyphus hesperus (Heteroptera: Miridae) in tomato greenhouses". Biological Control (3): 313–319. doi:10.1016/S1049-9644(03)00116-6. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help); Unknown parameter |volme= ignored (help)
  36. ^ "HOSTS - a Database of the World's Lepidopteran Hostplants". The Natural History Museum. Retrieved 2006-12-17.
  37. ^ a b Silverman, Maida (1977). "Mullein". A City Herbal: Lore, Legend, & Uses of Common Weeds. pp. 99–104. ISBN 1-888123-00-1. {{cite book}}: External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help)
  38. ^ a b c d e f g h Grieve, Margaret (1971) [1931]. "Mullein, Great". A Modern Herbal. Vol. Volume 2: I-Z. Dover publication. ISBN 0486227995. Retrieved 2006-11-29. {{cite encyclopedia}}: |volume= has extra text (help)
  39. ^ a b c d e Hanrahan, Claire (2005). "Mullein". In Jacqueline L. Longe (ed.). The Gale encyclopedia of alternative medicine. Vol. Volume 3: L-R (2nd edition ed.). Detroit: Thomson Gale. ISBN 0787674273. Retrieved 2006-11-30. {{cite encyclopedia}}: |edition= has extra text (help); |volume= has extra text (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  40. ^ Drury, Susan (1991). "Plants and Wart Cures in England from the Seventeenth to the Nineteenth Century: Some Examples". Folklore. 102 (1): 97–100. ISSN 0015-587X.
  41. ^ Turker, Arzu Ucar (2002). "Biological activity of common mullein, a medicinal plant". Journal of Ethnopharmacology. 82 (2–3): 117–125. doi:10.1016/S0378-8741(02)00186-1. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  42. ^ "Mullein flower". The Commission E Monographs. American Botanical Council. February 1, 1990. Retrieved 2006-12-06. {{cite web}}: Check date values in: |date= (help)
  43. ^ a b "Verbascum thapsus". Plants For A Future. Retrieved 2006-12-06.
  44. ^ Kay, Margaret (1994). "Poisoning by Gordolobo". HerbalGram (32): 42. ISSN 0899-5648. {{cite journal}}: Unknown parameter |month= ignored (help)
  45. ^ In book 25, Pliny describes "two principal kinds [of verbascum]": Latin, English, thought to be V. thapsus and V. blattaria
  46. ^ Wilhelm, Gene (1974). "The mullein: Plant piscicide of the mountain folk culture". Geographic Review. 64 (2): 235–252. doi:10.2307/213812. {{cite journal}}: Unknown parameter |month= ignored (help)

External links

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