Drosera rotundifolia, the round-leaved sundew,[4] roundleaf sundew, or common sundew, is a carnivorous species of flowering plant that grows in bogs, marshes and fens. One of the most widespread sundew species, it has a circumboreal distribution, being found in all of northern Europe, much of Siberia, large parts of northern North America, Korea and Japan but is also found as far south as California, Mississippi and Alabama in the United States of America and in New Guinea.

Drosera rotundifolia

Secure  (NatureServe)[2]
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Caryophyllales
Family: Droseraceae
Genus: Drosera
Subgenus: Drosera subg. Drosera
Section: Drosera sect. Drosera
Species:
D. rotundifolia
Binomial name
Drosera rotundifolia
Synonyms[3]
List
    • Drosera belezeana E.G.Camus (1891)
    • Drosera corsica (Maire) A.W.Hill (1926)
    • Drosera septentrionalis (Scop.) Stokes (1812)
    • Rorella rotundifolia (L.) All. (1785)
    • Rossolis rotundifolia (L.) Moench (1794)
    • Rossolis septentrionalis Scop. (1771)

Description

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A Drosera rotundifolia leaf on a 0.1-inch grid

The leaves of the common sundew are arranged in a basal rosette. The narrow, hairy, 1.3-to-5.0-centimetre (0.51 to 1.97 in) long petioles support 4-to-10-millimetre (0.16 to 0.39 in) round laminae. The upper surface of the lamina is densely covered with red glandular hairs that secrete a sticky mucilage.

A typical plant has a diameter of around 3 to 5 centimetres (1.2 to 2.0 in), with a 5-to-25-centimetre (2.0 to 9.8 in) tall inflorescence. The flowers grow on one side of a single slender, hairless stalk that emanates from the centre of the leaf rosette. White or pink in colour, the five-petalled flowers produce 1.0-to-1.5-millimetre (0.039 to 0.059 in), light brown, slender, tapered seeds.[5]

In the winter, D. rotundifolia produces a hibernaculum to survive the cold conditions. This consists of a bud of tightly curled leaves at ground level.

Carnivory

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D. rotundifolia with the remains of a butterfly

The plant feeds on insects, which are attracted to the glistening drops of mucilage, loaded with a sugary substance, covering its leaves. It has evolved this carnivorous behaviour in response to its habitat, which is usually poor in nutrients or is so acidic that nutrient availability is severely decreased. The plant uses enzymes to dissolve the insects – which become stuck to the glandular tentacles – and extract ammonia (from proteins) and other nutrients from their bodies.[6] The ammonia replaces the nitrogen that other plants absorb from the soil, and plants that are placed in a high-nitrogen environment rely less upon nitrogen from captured insects.[7]

It has been assumed that insects were also attracted to the bright red color of the common sundew, but studies using artificial traps have suggested that color does not affect prey attraction.[8] New climates have been discovered with new plant growth but don’t have the food associated with the requirements for growth.  In areas that lack this food associated for growth, new studies have been conducted to determine how these plants are able to grow in these diverse climates where these plants area able to flourish.  In a study by L.M. Thoren et al. posted in New Phytologist, the carnivory of the Drosera rotundifolia was tested against growing conditions where the plant's insect prey was not sufficient to promote proper growth.  The group tested the plants ability to grow with limited prey but increased inorganic nutrients within the soil.  The results revealed the ability of the plant to utilize the nutrients over the normal prey which caused the reduction in carnivory investment of the plant.  These results showed that the plant would adapt to the current environment for growth utilizing available resources as food.[9]

Distribution

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Roundleaf sundew range (red = common; pink = scattered)

In North America, the common sundew is found in all parts of Canada except the Canadian Prairies and the tundra regions, southern Alaska, the Pacific Northwest, and along the Appalachian Mountains south to Georgia and Louisiana. In the western United States, roundleaf sundew is found in mountain fens as far south as the Sierra Nevada of California and in a disjunct cluster of fen occurrences in the Rocky Mountains of Colorado.[10] In the eastern United States, the sundew plant is found in parts stretching from Nova Scotia down the coast into Florida.  In addition to Georgia, plants are now being seen in Alabama and Mississippi.  West of the Mississippi River plants are located along the pacific coast from Alaska down the coast to California with new plants detected in Iowa, Minnesota and in two recently recorded sites in Gunnison County, Colorado and Bottineau County, North Dakota.[11]

It is found in much of Europe, including the British Isles, most of France, the Benelux nations, Germany, Denmark, Switzerland, Czech Republic, Poland, Belarus, the Baltic countries, Sweden and Finland, as well as northern portions of Italy, Portugal, Spain, Romania, mountain regions of Bulgaria and in Iceland and southern regions of Norway and Greenland. It is infrequent in Austria and Hungary, and some populations are scattered around the Balkans.

In Britain, this is the most common form of sundew and it can be found on Exmoor, Dartmoor, Sedgemoor, the Lake District, Shropshire, Pennines and in Scotland, among other places. It is usually found in bogs, marshes and in hollows or corries on the sides of mountains. It is the county flower of Shropshire.[12]

In Asia, it is found across Siberia and Japan, as well as parts of Turkey, the Caucasus region, the Kamchatka Peninsula southern parts of Korea, and parts of China. Populations can also be found on the islands of New Guinea and Mindanao.[13]

Habitat

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D. rotundifolia growing in sphagnum moss along with sedges and Equisetum

The common sundew thrives in wetlands such as marshes and fens.[14] It is also found in wet stands of black spruce, Sphagnum bogs, silty and boggy shorelines and wet sands. It prefers open, sunny or partly sunny habitats.

Conservation

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The round-leaved sundew is classified as Least Concern in the IUCN red list. In North America, it is considered endangered in the US states of Illinois and Iowa, exploitably vulnerable in New York, and threatened in Tennessee. [1]. The species is ranked S2, imperiled, in the state of Colorado.[15]

Cultivation

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D. rotundifolia is one of the temperate species of Drosera cultivated by growers interested in carnivorous plants. To be grown successfully, plants of the wild species must be given a substantial period of winter dormancy during which they form hibernacula. The cultivar D. rotundifolia 'Charles Darwin' can be grown more successfully without a period of dormancy.[16]

Medicinal properties

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Drosera rotundifolia at Brown's Lake Bog, Ohio.

According to D.H. Paper, et al.,[17] Drosera rotundifolia plant extracts show great efficacy as an anti-inflammatory and antispasmodic, more so than D. madagascariensis, as a result of the flavonoids such as hyperoside, quercetin and isoquercetin, but not the naphthoquinones present in the extracts. The flavonoids are thought[18] to affect the M3 muscarinic receptors in smooth muscle, causing the antispasmodic effects. Ellagic acid in D. rotundifolia extracts has also been shown to have antiangiogenic effects.

Notes

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  1. ^ Maiz-Tome, L. 2016. Drosera rotundifolia. The IUCN Red List of Threatened Species 2016: e.T168798A1232630. https://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T168798A1232630.en. Accessed on 29 March 2022.
  2. ^ "NatureServe Explorer 2.0". explorer.natureserve.org. Retrieved 29 March 2022.
  3. ^ "Drosera rotundifolia L." Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 7 March 2024.
  4. ^ BSBI List 2007 (xls). Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-06-26. Retrieved 2014-10-17.
  5. ^ Regents of the University of California (1993). The Jepson Manual: Higher Plants of California. Berkeley, California: University of California Press.
  6. ^ "Drosera rotundifolia : Round-Leafed Sundew". msu.edu. Retrieved May 22, 2017.
  7. ^ Millett, J.; Svensson, B. M.; Newton, J.; Rydin, H. (July 2012). "Reliance on prey-derived nitrogen by the carnivorous plant Drosera rotundifolia decreases with increasing nitrogen deposition". New Phytologist. 195 (1): 182–188. doi:10.1111/j.1469-8137.2012.04139.x. PMID 22506640. Retrieved May 22, 2017.
  8. ^ Foot, G.; Rice, S. P.; Millett, J. (16 April 2014). "Red trap colour of the carnivorous plant Drosera rotundifolia does not serve a prey attraction or camouflage function". Biology Letters. 10 (4): 20131024. doi:10.1098/rsbl.2013.1024. PMC 4013691. PMID 24740904.
  9. ^ Thorén, L. Magnus; Tuomi, Juha; Kämäräinen, Terttu; Laine, Kari (2003–2008). "Resource availability affects investment in carnivory in Drosera rotundifolia". New Phytologist. 159 (2): 507–511. doi:10.1046/j.1469-8137.2003.00816.x. ISSN 0028-646X. PMID 33873350.
  10. ^ Wolf, Evan; Gage, Edward; Cooper, David (2006-06-26). "Drosera rotundifolia L. (roundleaf sundew): A Technical Conservation Assessment" (PDF). USDA Forest Service, Rocky Mountain Region, Species Conservation Project.
  11. ^ "Drosera rotundifolia". www.fs.usda.gov. Retrieved 2022-12-03.
  12. ^ "Round-leaved sundew | Plant & fungi species | Wild plants". www.plantlife.org.uk. Archived from the original on 2010-10-06. Retrieved 2016-01-03.
  13. ^ Coritico, Fulgent; Fleischmann, Andreas (January 2016). "The first record of the boreal bog species Drosera rotundifolia (Droseraceae) from the Philippines, and a key to the Philippine sundews". Blumea. 61 (1): 24–28. doi:10.3767/000651916X691330. Retrieved 10 December 2021.
  14. ^ C.Michael Hogan. 2011. Drosera rotundifolia. Encyclopedia of Earth. Eds. M.McGinley & C.J.Cleveland. National Council for Science and the Environment. Washington DC
  15. ^ "USFS species evaluation" (PDF).
  16. ^ Brittnacher, John. "Growing cold temperate Drosera". International Carnivorous Plant Society. Retrieved 2013-06-19.
  17. ^ Paper, D.H.; Karall, E.; Kremser, M.; Krenn, L. (April 2005). "Comparison of the antiinflammatory effects of Drosera rotundifolia and Drosera madagascariensis in the HET-CAM assay". Phytotherapy Research. 19 (4): 323–6. doi:10.1002/ptr.1666. PMID 16041727. S2CID 20405232.
  18. ^ Krenn L, Beyer G, Pertz HH, et al. (2004). "In vitro antispasmodic and anti-inflammatory effects of Drosera rotundifolia". Arzneimittelforschung. 54 (7): 402–5. doi:10.1055/s-0031-1296991. PMID 15344845.

References

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  Media related to Drosera rotundifolia at Wikimedia Commons