Editing Drosera

{{short description|Genus of carnivorous flowering plants in the family Droseraceae}}
{{Other uses}}
{{Redirect|Sundew}}
{{automatic taxobox
| image = Drosera_spatulata_KansaiHabit.jpg
| image_caption = ''[[Drosera tokaiensis]]''
| taxon = Drosera
| authority = [[Carl Linnaeus|L.]]
| subdivision_ranks = Subgenera
| subdivision =
* ''[[Drosera subg. Acturia|Acturia]]''
* ''[[drosera burmanni subg. Bryastrum|Bryastrum]]''
* ''[[Drosera subg. Coelophylla|Coelophylla]]''
* ''[[Drosera subg. Drosera|Drosera]]''
* ''[[Drosera subg. Ergaleium|Ergaleium]]''
* ''[[Drosera subg. Lasiocephala|Lasiocephala]]''
* ''[[Drosera subg. Meristocaulis|Meristocaulis]]''
* ''[[Drosera subg. Phycopsis|Phycopsis]]''
* ''[[Drosera subg. Regiae|Regiae]]''
* ''[[Drosera subg. Stelogyne|Stelogyne]]''
* ''[[Drosera subg. Thelocalyx|Thelocalyx]]''
| synonyms =  
*''Adenopa'' <small>Raf.</small>
*''Dismophyla'' <small>Raf.</small>
*''Drossera'' <small>Gled.</small>
*''Esera'' <small>Neck.</small>
*''Filicirna'' <small>Raf.</small>
*''Freatulina'' <small>Chrtek & Slavíková</small>
*''Rorella'' <small>Hill</small>
*''Rossolis'' <small>Adans.</small>
*''Sondera'' <small>Lehm.</small>
| synonyms_ref = <ref name="POWO-2023">{{cite web |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30001036-2 |title=''Drosera'' L. |date=2023 |website=Plants of the World Online |publisher=[[Royal Botanic Gardens, Kew]] |access-date=13 January 2023}}</ref>
}}

'''''Drosera''''', which is  commonly known as the '''sundews''', is one of the largest [[genus|genera]] of [[carnivorous plant]]s, with at least 194 [[species]].<ref name="McPherson-2010">{{cite book|last1=McPherson |first1= S.R.|year=2010|title=Carnivorous Plants and their Habitats|publisher=Redfern Natural History Productions Ltd.|location=Poole, England, UK}} 2 volumes.</ref> These members of the family [[Droseraceae]]<ref name="POWO-2023"/> lure, capture, and digest insects using stalked [[mucilage|mucilaginous]] glands covering their leaf surfaces. The insects are used to supplement the poor mineral nutrition of the soil in which the plants grow. Various species, which vary greatly in size and form, are native to every continent except [[Antarctica]].<ref name="McPherson-2008">{{cite book|last1=McPherson |first1= S.R. |year=2008 |title=Glistening Carnivores |location=Poole, England, UK |publisher=Redfern Natural History Productions Ltd.}}</ref>

[[Charles Darwin]] performed much of the early research into ''Drosera'', engaging in a long series of experiments with ''[[Drosera rotundifolia]]'' which were the first to confirm carnivory in plants.<ref name="Pain-2022">{{cite journal |last1=Pain |first1=Stephanie |title=How plants turned predator |journal=Knowable Magazine |date=2 March 2022 |doi=10.1146/knowable-030122-1|doi-access=free |url=https://knowablemagazine.org/article/living-world/2022/how-plants-turned-predator |access-date=11 March 2022}}</ref><ref name="Hedrich-2021">{{cite journal |last1=Hedrich |first1=Rainer |last2=Fukushima |first2=Kenji |title=On the Origin of Carnivory: Molecular Physiology and Evolution of Plants on an Animal Diet |journal=Annual Review of Plant Biology |date=17 June 2021 |volume=72 |issue=1 |pages=133–153 |doi=10.1146/annurev-arplant-080620-010429 |pmid=33434053 |s2cid=231595236 |issn=1543-5008|doi-access=free |bibcode=2021AnRPB..72..133H }}</ref><ref name="Darwin-1875" />  In an 1860 letter, Darwin wrote, “…at the present moment, I care more about ''Drosera'' than the origin of all the species in the world.”<ref>{{Cite journal|last1=Ellison|first1=Aaron M.|last2=Gotelli|first2=Nicholas J.|date=1 January 2009|title=Energetics and the evolution of carnivorous plants—Darwin's 'most wonderful plants in the world'|url=https://academic.oup.com/jxb/article/60/1/19/567619|journal=Journal of Experimental Botany|language=en|volume=60|issue=1|pages=19–42|doi=10.1093/jxb/ern179|issn=0022-0957|doi-access=free|pmid=19213724}}</ref>

== Taxonomy ==
The botanical name from the [[Ancient Greek|Greek]] {{lang|el|δρόσος}} ''drosos'' "dew, dewdrops"<ref>{{cite web|url=http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=dro/sos |title=δρόσος |last1=Liddell |first1=Henry George |last2=Scott|first2=Robert |work=A Greek-English Lexicon |publisher=Perseus Digital Library |date= 1940 }}</ref> refer to the glistening drops of [[mucilage]] at the tip of the glandular [[trichome]]s that resemble drops of morning [[dew]]. The English common name ''sundew'' also describes this, derived from [[Latin]] ''ros solis'' meaning "dew of the sun".

The ''Principia Botanica'', published in 1787, states “Sun-dew (''Drosera'') derives its name from small drops of a liquor-like dew, hanging on its fringed leaves, and continuing in the hottest part of the day, exposed to the sun.”<ref name="Darwin the Elder-1787">{{cite book |last1=Darwin, the Elder |first1=Robert Waring |title=Principia Botanica; Or, A Concise and Easy Introduction to the Sexual Botany of Linnæus, Etc. [The Preface Signed: R. W. D., I.e. Robert W. Darwin, the Elder.] |date=1787 |publisher=Allin & Company |location=Newark |url=https://books.google.com/books?id=LPpeAAAAcAAJ |access-date=14 March 2022 |language=en}}</ref>

=== Phylogenetics ===
{{main|Taxonomy of Drosera|List of Drosera species}}
The unrooted [[cladogram]] to the right shows the relationship between various subgenera and classes as defined by the analysis of Rivadavia ''et al.''<ref name="Hasebe, Mitsuyasu-2003" /> The monotypic section ''[[Meristocaulis]]'' was not included in the study, so its place in this system is unclear. More recent studies have placed this group near section ''Bryastrum'', so it is placed there below. Also of note, the placement of the section ''Regiae'' in relation to ''Aldrovanda'' and ''Dionaea'' is uncertain. Since the section ''Drosera'' is [[polyphyletic]], it shows up multiple times in the cladogram '''(*)'''.

This phylogenetic study has made the need for a revision of the genus even clearer.{{Cladogram|style="float:right;"
|clades={{Clade| style=font-size:75%;line-height:75%
|label1=''Drosera''
| 1 = {{Clade
 | 1 = {{Clade
 | 1 = {{Clade
 | 1 = {{Clade
 | 1 = {{Clade
 |label1= Subgenus ''Drosera''
 | 1 ={{Clade 
 |1 =  [[Drosera sect. Drosera|Section ''Drosera'']]
 |2 =[[Drosera sect. Arachnopus|Section ''Arachnopus'']]
 |3=[[Drosera sect. Prolifera|Section ''Prolifera'']]
}}
 }}
 | 2 = [[Drosera sect. Thelocalyx|Section ''Thelocalyx'']]
 }}
 | 2 = {{Clade
 | 1 = {{Clade
 | 1 = [[Drosera subg. Ergaleium|Subgenus ''Ergaleium'']]
 | 2 = [[Drosera subg. Phycopsis|Subgenus ''Phycopsis'']]
 }}
 | 2 = {{Clade
 | 1 = {{Clade
 |label1= Subgenus ''Bryastrum''
 | 1 = {{Clade 
 |1 =[[Drosera sect. Bryastrum|Section ''Bryastrum'']]
 |2 =[[Drosera sect. Lamprolepis|Section ''Lamprolepis'']]
}}
 | 2 = [[Drosera sect. Lasiocephala|Section ''Lasiocephala'']]
 }}
 | 2 = [[Drosera sect. Coelophylla|Section ''Coelophylla'']]
 }}
 }}
 }}
 | 2 = Section ''Drosera'': ''[[Drosera arcturi]]''*
 }}
 | 2 = {{Clade
 | 1 = Section ''Regiae'': ''[[Drosera regia]]''*
 | 2 = ''[[Aldrovanda]]''
 }}
 }}
| 2 = ''[[Venus flytrap|Dionaea]]''
}}
}}

== Description ==
[[File:DroseraZonariaTuber2-.jpg|thumb|upright|A tuber of ''[[Drosera zonaria|D. zonaria]]'', a tuberous sundew, beginning its winter growth]]
Sundews are [[perennial plant|perennial]] (or rarely [[Annual plant|annual]]) [[herbaceous plant]]s, typically forming prostrate or upright rosettes between {{convert|1|and|100|cm||abbr=on}} in height, depending on the species. Climbing species form scrambling stems which can reach much longer lengths, up to {{convert|3|m|ft|abbr=on}} in the case of ''[[Drosera erythrogyne|D.&nbsp;erythrogyne]]''.<ref name="Mann-2001">{{cite journal |last1=Mann |first1=Phill |title=The world's largest Drosera |journal=Carnivorous Plant Newsletter |date=2001 |volume=30 |issue=3 |page=79 |url=http://www.cephalotus.net/article.aspx?cid=12&y=2001&m=10&d=22 |access-date=2022-08-17 |archive-date=2011-09-29 |archive-url=https://archive.today/20110929000000/http://www.cephalotus.net/article.aspx?cid=12&y=2001&m=10&d=22 |url-status=dead }}</ref> Sundews have been shown to be able to achieve a lifespan of 50 years.<ref name="Barthlott-2004">{{cite book |last1=Barthlott |first1=Wilhelm |last2=Porembski |first2=Stefan |last3=Seine |first3=Rüdiger |last4=Theisen |first4=Inge |title=Karnivoren Biologie und Kultur fleischfressender Pflanzen |date=1 June 2004 |publisher=Verlag Eugen Ulmer |location=Stuttgart (Hohenheim) |isbn=9783800141449}}</ref>{{rp|102}} The genus is specialized for [[nutrient]] uptake through its carnivorous behavior, for example the pygmy sundew is missing the [[enzyme]]s ([[nitrate reductase]], in particular)<ref name="Karlsson-1992">{{cite journal |last1=Karlsson |first1=PS |last2=Pate |first2=JS |title=Contrasting effects of supplementary feeding of insects or mineral nutrients on the growth and nitrogen and phosphorous economy of pygmy species of Drosera. |journal=Oecologia |date= 1992 |volume=92 |issue=1 |pages=8–13 |doi=10.1007/BF00317256 |pmid=28311806 | bibcode=1992Oecol..92....8K | s2cid=13038192 }}</ref> that plants normally use for the uptake of earth-bound nitrates.

=== Growth form<!--as in growth form, NOT Habitat, as in location--> ===
The genus can be divided into several [[habit (biology)|habits]], or growth forms:
* Temperate sundews: These species form a tight cluster of unfurled leaves called a [[hibernaculum (botany)|hibernaculum]] in a winter dormancy period (= [[Hemicryptophyte]]). All of the North American and European species belong to this group. ''Drosera arcturi'' from Australia (including Tasmania) and New Zealand is another temperate species that dies back to a horn-shaped hibernaculum.
* Subtropical sundews: These species maintain vegetative growth year-round under uniform or nearly uniform climatic conditions.
* Pygmy sundews: A group of roughly 40 Australian species, they are distinguished by miniature growth, the formation of [[Gemma (botany)|gemmae]] for [[asexual reproduction]], and dense formation of hairs in the crown center. These hairs serve to protect the plants from Australia's intense summer sun. Pygmy sundews form the subgenus ''[[Drosera subg. Bryastrum|Bryastrum]]''.
* Tuberous sundews: These nearly 50 Australian species form an underground [[tuber]] to survive the extremely dry summers of their habitat, re-emerging in the autumn. These so-called tuberous sundews can be further divided into two groups, those that form rosettes and those that form climbing or scrambling stems. Tuberous sundews comprise the subgenus ''[[Drosera subg. Ergaleium|Ergaleium]]''.
[[File:Drosera derbyensis ne1.JPG|thumb|''[[Drosera derbyensis|D. derbyensis]]'', from the petiolaris complex]]
* ''Petiolaris'' complex: A group of tropical Australian species, they live in constantly warm but sometimes wet conditions. Several of the 14 species that comprise this group have developed special strategies to cope with the alternately drier conditions. Many species, for example, have [[Petiole (botany)|petioles]] densely covered in [[trichome]]s, which maintain a sufficiently humid environment and serve as an increased [[condensation]] surface for morning dew. The ''Petiolaris'' complex comprises the subgenus ''[[Drosera subg. Lasiocephala|Lasiocephala]]''.

Although they do not form a single strictly defined growth form, a number of species are often put together in a further group:
* Queensland sundews: A small group of three species (''[[Drosera adelae|D.&nbsp;adelae]]'', ''[[Drosera schizandra|D.&nbsp;schizandra]]'' and ''[[Drosera prolifera|D.&nbsp;prolifera]]''), all are native to highly humid habitats in the dim understories of the Australian rainforest.

=== Leaves and carnivory ===
[[File:Drosera capensis bend.JPG|thumb|upright|Leaf and tentacle movement on ''[[Drosera capensis|D. capensis]]'']]
Sundews are characterised by the glandular tentacles, topped with sticky secretions, that cover their [[Leaf|leaves]]. The trapping and digestion mechanism usually employs two types of glands: stalked glands that secrete sweet mucilage to attract and ensnare insects and enzymes to digest them, and [[Sessility (botany)|sessile]] [[gland]]s that absorb the resulting nutrient soup (the latter glands are missing in some species, such as ''[[Drosera erythrorhiza|D.&nbsp;erythrorhiza]]''). Small prey, mainly consisting of insects, are attracted by the sweet secretions of the peduncular glands. Upon touching these, the prey become entrapped by sticky mucilage which prevents their progress or escape. Eventually, the prey either succumb to death through exhaustion or through asphyxiation as the mucilage envelops them and clogs their [[Spiracle (arthropods)|spiracle]]s. Death usually occurs within 15 minutes.<ref name="Darwin-1875">{{cite book| author-first=Charles |author-last=Darwin | title=Insectivorous Plants
| year=1875| location=London|publisher= John Murray  |url=http://darwin-online.org.uk/EditorialIntroductions/Freeman_InsectivorousPlants.html |access-date= March 14, 2022}}</ref> The plant meanwhile secretes [[esterase]], [[peroxidase]], [[phosphatase]] and [[protease]] [[enzymes]].<ref name="Barthlott-2004" />{{rp|41}} These enzymes dissolve the insect and free the nutrients contained within it. This nutrient mixture is then absorbed through the leaf surfaces to be used by the rest of the plant.
 [[File:Drosera Glandular Hair.jpg|thumb|Drosera Glandular Hair]]                                                                                    
All species of sundew are able to move their tentacles in response to contact with edible prey. The tentacles are extremely sensitive and will bend toward the center of the leaf to bring the insect into contact with as many stalked glands as possible. According to [[Charles Darwin]], the contact of the legs of a small gnat with a single tentacle is enough to induce this response.<ref name="Darwin-1875"/> This response to touch is known as [[thigmonasty]], and is quite rapid in some species. The outer tentacles (recently coined as "snap-tentacles") of ''[[Drosera burmanni|D.&nbsp;burmanni]]'' and ''[[Drosera sessilifolia|D.&nbsp;sessilifolia]]'' can bend inwards toward prey in a matter of seconds after contact, while ''[[Drosera glanduligera|D.&nbsp;glanduligera]]'' is known to bend these tentacles in toward prey in tenths of a second.<ref>Hartmeyer, I. & Hartmeyer, S., (2005) Drosera glanduligera: Der Sonnentau mit "Schnapp-Tentakeln", DAS TAUBLATT (GFP) 2005/2: 34-38</ref> In addition to tentacle movement, some species are able to bend their leaves to various degrees to maximize contact with the prey. Of these, ''[[Drosera capensis|D.&nbsp;capensis]]'' exhibits what is probably the most dramatic movement, curling its leaf completely around prey in 30 minutes. Some species, such as ''[[Drosera filiformis|D.&nbsp;filiformis]]'', are unable to bend their leaves in response to prey.<ref name="D'Amato, Peter-1998">{{cite book | author=D'Amato, Peter | title=The Savage Garden: Cultivating Carnivorous Plants | publisher=Ten Speed Press | location=Berkeley, California | year=1998 | isbn=978-0-89815-915-8 | title-link=The Savage Garden: Cultivating Carnivorous Plants }}</ref>

[[File:DroseraIndicaEmergences.JPG|thumb|Emergences of an Australian ''[[Drosera indica|D. indica]]'']]
A further type of (mostly strong red and yellow) leaf coloration has recently been discovered in a few Australian species (''[[Drosera hartmeyerorum|D. hartmeyerorum]]'', ''[[Drosera indica|D. indica]]''). Their function is not known yet, although they may help in attracting prey.

The leaf morphology of the species within the genus is extremely varied, ranging from the sessile [[:File:Leaf morphology no title.png|ovate]] leaves of ''D. erythrorhiza'' to the bipinnately divided [[:File:Leaf morphology no title.png|acicular]] leaves of ''[[Drosera binata|D. binata]]''.

While the exact physiological mechanism of the sundew's carnivorous response is not yet known, some studies have begun to shed light on how the plant is able to move in response to mechanical and chemical stimulation to envelop and digest prey. Individual tentacles, when mechanically stimulated, fire action potentials that terminate near the base of the tentacle, resulting in rapid movement of the tentacle towards the center of the leaf.<ref>{{Cite journal|last1=Williams|first1=Stephen E.|last2=Pickard|first2=Barbara G.|date=1972|title=Receptor potentials and action potentials in Drosera tentacles|journal=Planta|volume=103|issue=3|pages=193–221|doi=10.1007/bf00386844|pmid=24481555|bibcode=1972Plant.103..193W |s2cid=2155695|issn=0032-0935}}</ref><ref name="Williams-1980">{{cite book |last1=Williams |first1=S. E. |last2=Pickard |first2=B. G. |chapter= The Role of Action Potentials in the Control of Capture Movements of Drosera and Dionaea|title= Plant Growth Substances 1979|series=Proceedings in Life Sciences |date=1980 |pages=470–480 |doi=10.1007/978-3-642-67720-5_48|isbn=978-3-642-67722-9 }}</ref> This response is more prominent when marginal tentacles further away from the leaf center are stimulated. The tentacle movement response is achieved through auxin-mediated [[acid growth]]. When action potentials reach their target cells, the plant hormone [[auxin]] causes protons (H<sup>+</sup> ions) to be pumped out of the plasma membrane into the cell wall, thereby reducing the pH and making the cell wall more acidic.<ref>{{Cite journal|last1=Rayle|first1=D. L.|last2=Cleland|first2=R. E.|date=1992-08-01|title=The Acid Growth Theory of auxin-induced cell elongation is alive and well.|journal=Plant Physiology|volume=99|issue=4|pages=1271–1274|doi=10.1104/pp.99.4.1271|issn=0032-0889|pmid=11537886|pmc=1080619}}</ref> The resulting reduction in pH causes the relaxation of the cell wall protein, expansin, and allows for an increase in cell volume via osmosis and turgor. As a result of differential cell growth rates, the sundew tentacles are able to achieve movement towards prey and the leaf center through the bending caused by expanding cells.<ref>{{Cite journal|last=Hooker|first=Henry D.|date=1917|title=Mechanics of Movement in Drosera rotundifolia|jstor=2479748|journal=Bulletin of the Torrey Botanical Club|volume=44|issue=8|pages=389–403|doi=10.2307/2479748}}</ref>  Among some ''Drosera'' species, a second bending response occurs in which non-local, distant tentacles bend towards prey as well as the bending of the entire leaf blade to maximize contact with prey. While mechanical stimulation is sufficient to achieve a localized tentacle bend response, both mechanical and chemical stimuli are required for the secondary bending response to occur.<ref>{{Cite journal|last1=Krausko|first1=Miroslav|last2=Perutka|first2=Zdeněk|last3=Šebela|first3=Marek|last4=Šamajová|first4=Olga|last5=Šamaj|first5=Jozef|last6=Novák|first6=Ondřej|last7=Pavlovič|first7=Andrej|date=March 2017|title=The role of electrical and jasmonate signalling in the recognition of captured prey in the carnivorous sundew plant Drosera capensis|journal=The New Phytologist|volume=213|issue=4|pages=1818–1835|doi=10.1111/nph.14352|issn=1469-8137|pmid=27933609|doi-access=free|bibcode=2017NewPh.213.1818K }}</ref>

=== Flowers and fruit ===
[[File:DroseraKenneallyiFlora.jpg|thumb|Flower of ''[[Drosera kenneallyi|D. kenneallyi]]'']]
The flowers of sundews, as with nearly all carnivorous plants, are held far above the leaves by a long stem. This physical isolation of the flower from the traps is commonly thought to be an adaptation meant to avoid trapping potential [[pollinator]]s. The mostly unforked [[inflorescence]]s are [[raceme|spikes]], whose flowers open one at a time and usually only remain open for a short period. Flowers open in response to light intensity (often opening only in direct sunlight), and the entire inflorescence is also [[heliotropism|heliotropic]], moving in response to the sun's position in the sky.
[[File:Drosera with flower stem.jpg|alt=Multiple drosera plants with long flower stalks|thumb|Multiple ''drosera'' plants with long flower stalks]]
The [[Symmetry (biology)#Radial symmetry|radially symmetrical]] ([[actinomorphic]]) flowers are always [[Perfect flower|perfect]] and have five parts (the exceptions to this rule are the four-petaled ''[[Drosera pygmaea|D. pygmaea]]'' and the eight to 12-petaled ''[[Drosera heterophylla|D. heterophylla]]''). Most of the species have small flowers (<1.5&nbsp;cm or 0.6&nbsp;in). A few species, however, such as ''[[Drosera regia|D. regia]]'' and ''[[Drosera cistiflora|D. cistiflora]]'', have flowers {{convert|4|cm|in|abbr=on}} or more in diameter.<ref name="D'Amato, Peter-1998" /> In general, the flowers are white or pink. Australian species display a wider range of colors, including orange (''[[Drosera callistos|D. callistos]]''), red (''[[Drosera adelae|D. adelae]]''), yellow (''[[Drosera zigzagia|D. zigzagia]]'') or metallic violet (''[[Drosera microphylla|D. microphylla]]'').

The [[Ovary (plants)|ovary]] is [[Ovary (plants)|superior]] and develops into a [[Dehiscence (botany)#Fruit dehiscence|dehiscent]] [[Capsule (fruit)|seed capsule]] bearing numerous tiny seeds. The [[pollen]] grain type is compound, which means four [[microspore]]s (pollen grains) are stuck together with a protein called [[callose]].{{Citation needed|date=May 2012}}

=== Roots ===
[[File:Drosera anglica ne2.jpg|thumb|''Drosera anglica'' with prey]]
The root systems of most ''Drosera'' are often only weakly developed or have [[vestigiality|lost their original functions]].<ref name="Adlassnig-2005">{{cite journal |last1=Adlassnig |first1=Wolfram |last2=Peroutka |first2=Marianne |last3=Lambers |first3=Hans |last4=Lichtscheidl |first4=Irene K. |date=July 2005 |title=The Roots of Carnivorous Plants |url=https://link.springer.com/article/10.1007/s11104-004-2754-2 |journal=Plant and Soil |volume=274 |issue=1–2 |pages=127–140 |doi=10.1007/s11104-004-2754-2|bibcode=2005PlSoi.274..127A |s2cid=5038696 |url-access=subscription }}</ref> They are relatively useless for nutrient uptake, and they serve mainly to absorb water and to anchor the plant to the ground; they have long [[root hair|hair]]s.<ref name="Adlassnig-2005"/>

A few South African species use their roots for water and food storage. Some species have wiry root systems that remain during frosts if the stem dies. Some species, such as ''D. adelae'' and ''[[Drosera hamiltonii|D. hamiltonii]]'', use their roots for asexual propagation, by sprouting plantlets along their length. Some Australian species form underground [[corm]]s for this purpose, which also serve to allow the plants to survive dry summers. The roots of pygmy sundews are often extremely long in proportion to their size, with a 1-cm (0.4-in) plant extending roots over {{convert|15|cm|in|abbr=on}} beneath the soil surface. Some pygmy sundews, such as ''[[Drosera lasiantha|D. lasiantha]]'' and ''[[Drosera scorpioides|D. scorpioides]]'', also form [[adventitious root]]s as supports.

''[[Drosera intermedia|D. intermedia]]'' and ''[[Drosera rotundifolia|D. rotundifolia]]'' have been reported to form [[arbuscular mycorrhiza]]e, which penetrate the plant's tissues,<ref name="Wang-2006">{{cite journal |last1=Wang |first1=B. |last2=Qiu |first2=Y.-L. |title=Phylogenetic distribution and evolution of mycorrhizas in land plants |journal=Mycorrhiza |date=July 2006 |volume=16 |issue=5 |pages=299–363 |doi=10.1007/s00572-005-0033-6|pmid=16845554 |bibcode=2006Mycor..16..299W |s2cid=30468942 }}</ref> they also host fungi like [[endophyte]]s to collect nutrients when they grow in poor soil and form [[symbiosis|symbiotic relationships]].<ref>{{cite journal |last1=Quilliam |first1=Richard S. |last2=Jones |first2=David L. |title=Fungal root endophytes of the carnivorous plant Drosera rotundifolia |url=https://link.springer.com/article/10.1007/s00572-009-0288-4 |journal=Mycorrhiza |date=June 2010 |volume=20 |issue=5 |pages=341–348 |doi=10.1007/s00572-009-0288-4 |pmid=20012108 |bibcode=2010Mycor..20..341Q |s2cid=11825262 |url-access=subscription }}</ref>

== Reproduction ==
Many species of sundews are self-fertile; their flowers will often self-pollinate upon closing. Often, numerous seeds are produced. The tiny black seeds germinate in response to moisture and light, while seeds of temperate species also require cold, damp, [[stratification (botany)|stratification]] to germinate. Seeds of the tuberous species require a hot, dry summer period followed by a cool, moist winter to germinate.

[[Vegetative reproduction]] occurs naturally in some species that produce [[stolons]] or when roots come close to the surface of the soil. Older leaves that touch the ground may sprout plantlets. Pygmy sundews reproduce asexually using specialized scale-like leaves called [[gemma (botany)|gemmae]]. Tuberous sundews can produce offsets from their corms.<ref name="D'Amato, Peter-1998" />

In culture, sundews can often be propagated through leaf, crown, or root cuttings, as well as through seeds.<ref name="D'Amato, Peter-1998" />

== Distribution ==
{{see also|Carnivorous plants of Australia}}
[[File:Drosera distribution.svg|thumb|upright=1.25|Distribution of the genus ''Drosera'' shown in green]]
[[File:Drosera filiformis, NJ.jpg|thumb|''Drosera filiformis'' var. ''filiformis'' in a peat bog in New Jersey]]
The [[Range (biology)|range]] of the sundew genus stretches from Alaska in the north to New Zealand in the south. The centers of [[Biodiversity|diversity]] are Australia, with roughly 50% of all known species, and South America and southern Africa, each with more than 20 species. A few species are also found in large parts of Eurasia and North America. These areas, however, can be considered to form the outskirts of the generic range, as the ranges of sundews do not typically approach temperate or Arctic areas. Contrary to previous supposition, the evolutionary [[speciation]] of this genus is no longer thought to have occurred with the breakup of [[Gondwana]] through [[continental drift]]. Rather, speciation is now thought to have occurred as a result of a subsequent wide dispersal of its range.<ref name="Hasebe, Mitsuyasu-2003">{{cite journal | author= Rivadavia, Fernando | author2= Kondo, Katsuhiko | author3= Kato, Masahiro | author4= Hasebe, Mitsuyasu | name-list-style=amp| title= Phylogeny of the sundews, ''Drosera'' (Droseraceae), based on chloroplast rbcL and nuclear 18S ribosomal DNA Sequences | journal=[[American Journal of Botany]] | volume=90 | year=2003 | pages=123–130 | doi= 10.3732/ajb.90.1.123  | issue=1 | pmid=21659087| doi-access=free }}</ref> The origins of the genus are thought to have been in Africa or Australia.<ref name="Hasebe, Mitsuyasu-2003" />

Europe is home to only three species: ''[[Drosera intermedia|D. intermedia]]'', ''[[Drosera anglica|D. anglica]]'', and ''[[Drosera rotundifolia|D. rotundifolia]]''. Where the ranges of the two latter species overlap, they sometimes hybridize to form the sterile ''[[Drosera anglica#Hybrids|D. × obovata]]''. In addition to the three species and the hybrid native to Europe, North America is also home to four additional species; ''[[Drosera brevifolia|D. brevifolia]]'' is a small [[Annual plant|annual]] native to coastal states from [[Texas]] to [[Virginia]], while ''[[Drosera capillaris|D. capillaris]]'', a slightly larger plant with a similar range, is also found in areas of the Caribbean. The third species, ''[[Drosera linearis|D. linearis]]'', is native to the northern United States and southern Canada. ''[[Drosera filiformis|D. filiformis]]'' has two [[subspecies]] native to the East Coast of North America, the [[Gulf Coast]], and the [[Florida panhandle]].

This genus is often described as [[cosmopolitan distribution|cosmopolitan]], meaning it has worldwide distribution. The botanist [[Ludwig Diels]], author of the only [[monograph]] of the family to date, called this description an "arrant misjudgment of this genus' highly unusual distributional circumstances (''arge Verkennung ihrer höchst eigentümlichen Verbreitungsverhältnisse'')", while admitting sundew species do "occupy a significant part of the Earth's surface (''einen beträchtlichen Teil der Erdoberfläche besetzt'')".<ref name="Diels-1906">{{cite journal |last1=Diels |first1=Friedrich Ludwig Emil |title=Droseraceae
|journal=Das Pflanzenreich 
|editor-last=Engler 
|editor-first= Adolf
|volume=  IV
|issue= 112 
|date=1906 
|url=https://bibdigital.rjb.csic.es/en/records/item/10988-droseraceae-in-engler-das-pflanzenreich-heft-26-iv-112?offset=2 |access-date=14 March 2022}}</ref> 
He particularly pointed to the absence of ''Drosera'' species from almost all [[arid]] climate zones, countless [[rainforest]]s, the American Pacific Coast, [[Polynesia]], the Mediterranean region, and North Africa, as well as the scarcity of species diversity in temperate zones, such as Europe and North America.<ref name="Diels-1906" />

== Habitat ==
[[File:Drosera rotundifolia habitat.jpg|thumb|Round-leaved sundew (''[[Drosera rotundifolia|D. rotundifolia]]'') growing in sphagnum moss along with [[sedges]] and ''[[Equisetum]]'' in [[Mt. Hood National Forest]], [[Oregon]]]]
Sundews generally grow in seasonally moist or more rarely constantly wet habitats with acidic soils and high levels of sunlight. Common habitats include [[bog]]s, [[fen]]s, [[swamp]]s, [[marsh]]es, the [[tepui]]s of Venezuela, the [[wallum]]s of coastal Australia, the [[fynbos]] of South Africa, and moist streambanks. Many species grow in association with [[sphagnum moss]], which absorbs much of the soil's nutrient supply and also acidifies the soil, making nutrients less available to plant life. This allows sundews, which do not rely on soil-bound nutrients, to flourish where more dominating vegetation would usually outcompete them.

The genus, though, is very variable in terms of habitat. Individual sundew species have adapted to a wide variety of environments, including atypical habitats, such as rainforests, deserts (''[[Drosera burmanni|D. burmanni]]'' and ''[[Drosera indica|D. indica]]''), and even highly shaded environments (Queensland sundews). The temperate species, which form [[hibernaculum (botany)|hibernacula]] in the winter, are examples of such adaptation to habitats; in general, sundews tend to inhabit warm climates, and are only moderately frost-resistant.

== Conservation status ==

[[File:Drosera rotundifolia leaf1.jpg|thumb|Leaf of the round-leaved sundew, ''[[Drosera rotundifolia]]'']]

Protection of the genus varies between countries. None of the ''Drosera'' species in the United States are federally protected. Some are listed as [[Threatened species|threatened]] or [[Endangered species|endangered]] at the state level, but this gives little protection to lands under private ownership.<ref name="San Diego Zoo"/> Many of the remaining native populations are located on protected land, such as [[national park]]s or wildlife preserves.<ref name="NatureServe Explorer 2.0">{{cite web |title=Drosera anglica |url=https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.161038/Drosera_anglica |website=NatureServe Explorer 2.0 |access-date=15 March 2022}}</ref> ''Drosera'' species are protected by law in many European countries, such as Germany, Austria, Switzerland, the Czech Republic, Finland, [[Hungary]], [[France]], and Bulgaria.<ref name="Baranyai-2016">{{cite journal |last1=Baranyai |first1=B. |last2=Jooste |first2=H. |title=Biology, ecology, use, conservation and cultivation of round-leaved sundew (Drosera rotundifolia L.): a review |journal=Mires and Peat |date=2016 |volume=18 |pages=1–28 |url=http://mires-and-peat.net/media/map18/map_18_18.pdf}}</ref> In Australia, they are listed as "threatened".<ref name="AusGov">{{cite web |title=Drosera prolifera Glossary SPRAT Profile |url=https://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=9940 |website=Species Profile and Threats Database |publisher=Australian Government |access-date=15 March 2022}}</ref> In South America and the Caribbean, ''Drosera'' species in a number of areas are considered critical, endangered or vulnerable, while other areas have not been surveyed.<ref name="de Stefano-2001">{{cite journal |last1=de Stefano |first1=Rodrigo Duno |last2=dos Santos Silva |first2=Tania Regina |title=Conservation status of the carnivorous genus Drosera in South America and the Caribbean |journal=Harvard Papers in Botany |date=2001 |volume=6 |issue=1 |pages=253–260 |jstor=41761649 |url=https://www.jstor.org/stable/41761649 |access-date=15 March 2022 |issn=1043-4534}}</ref> At the same time that species are at risk in South Africa,<ref name="Cross-2020"/> new species continue to be discovered in the [[Western Cape]]<ref name="Fleischmann-2018">{{cite journal |last1=Fleischmann |first1=Andreas |title=Drosera xerophila ( Droseraceae ), a new species from Overberg District, South Africa, and an overview of the rosetted hemicryptophyte sundew species from Western Cape Province |journal=Willdenowia |date=April 2018 |volume=48 |issue=1 |pages=93–107 |doi=10.3372/wi.48.48106|s2cid=90715895 |doi-access=free |bibcode=2018Willd..48...93F }}</ref> and [[Madagascar]].<ref name="Fleischmann-2020">{{cite journal |last1=Fleischmann |first1=Andreas S. |last2=Rakotoarivelo |first2=Nivo H. |last3=Roccia |first3=Aymeric |last4=Gonella |first4=Paulo M. |last5=Andriamiarisoa |first5=Lala Roger |last6=Razanatsima |first6=Aina |last7=Rakotoarivony |first7=Fortunat |title=A new and endemic species of Drosera (Droseraceae) from Madagascar |journal=Plant Ecology and Evolution |pages=283–291 |date=2020|volume=153 |issue=2 |doi=10.5091/plecevo.2020.1705 |jstor=26927031 |s2cid=225539874 |doi-access=free |bibcode=2020PlEcE.153..283F }}</ref>

Worldwide, ''Drosera''  are at risk of extinction due to the destruction of natural habitat through urban and agricultural development. They are also threatened by the illegal collection of wild plants for the horticultural trade.<ref name="Cross-2020">{{cite journal |last1=Cross |first1=Adam T. |last2=Krueger |first2=Thilo A. |last3=Gonella |first3=Paulo M. |last4=Robinson |first4=Alastair S. |last5=Fleischmann |first5=Andreas S. |title=Conservation of carnivorous plants in the age of extinction |journal=Global Ecology and Conservation |date=1 December 2020 |volume=24 |pages=e01272 |doi=10.1016/j.gecco.2020.e01272 |s2cid=225228358 |language=en |issn=2351-9894 |quote="The most significant threats placing species at imminent risk of extinction include the continuing clearing of natural habitat for urban and agricultural development and the illegal collection of individuals from the wild for horticultural trade."|doi-access=free |bibcode=2020GEcoC..2401272C |hdl=20.500.11937/84611 |hdl-access=free }}</ref> An additional risk is [[climate change|environmental change]], because species are often specifically adapted to a precise location and set of conditions.<ref name="Cross-2020"/>

Currently, the largest threat in Europe and North America is loss of wetland habitat.<ref name="San Diego Zoo">{{cite web |title=Sundew |url=https://animals.sandiegozoo.org/plants/sundew |website=San Diego Zoo Animals & Plants |access-date=15 March 2022}}</ref><ref name="National Wildlife Federation">{{cite web |title=Sundews |url=https://www.nwf.org/Educational-Resources/Wildlife-Guide/Plants-and-Fungi/Sundews |website=The National Wildlife Federation |access-date=15 March 2022}}</ref> Causes include urban development and the draining of bogs for agricultural uses and peat harvesting.<ref name="Cross-2020"/>
Such threats have led to the extirpation of some species from parts of their former range. Reintroduction of plants into such habitats is usually difficult or impossible, as the ecological needs of certain populations are closely tied to their geographical location.<ref name="Cross-2020"/> Increased legal protection of bogs and moors,<ref name="Lausche-2011">{{cite book |last1=Lausche |first1=Barbara J. |title=Guidelines for Protected Areas Legislation |date=2011 |publisher=IUCN |location=Gland, Switzerland |isbn=978-2-8317-1245-1 |pages=143 |url=https://books.google.com/books?id=13gGb2rQVQwC&pg=PA143}}</ref> and a concentrated effort to renaturalize such habitats, are possible ways to combat threats to ''Drosera''  plants' survival.<ref name="Barbour-2007">{{cite book |last1=Barbour |first1=Michael |last2=Keeler-Wolf |first2=Todd |last3=Schoenherr |first3=Allan A. |title=Terrestrial Vegetation of California, 3rd Edition |date=17 July 2007 |publisher=University of California Press |isbn=978-0-520-24955-4 |url=https://books.google.com/books?id=YNAWPSMm2CUC&pg=PA116}}</ref> As part of the landscape, sundews are often overlooked or not recognized at all.<ref name="Newlin-2013">{{cite book |last1=Newlin |first1=William V. P. |last2=Cline |first2=Kenneth S. |last3=Briggs |first3=Rachel |last4=Namnoum |first4=A. Addison |last5=Ciccotelli |first5=Brett |title=The College of the Atlantic Guide to the Lakes and Ponds of Mt. Desert: Discovering the Freshwater Gems of Maine's Largest Island |date=27 August 2013 |publisher=North Atlantic Books |isbn=978-1-58394-797-5 |url=https://books.google.com/books?id=V8VvDwAAQBAJ&pg=PA283}}</ref><ref name="Harris-2020">{{cite web |last1=Harris |first1=Kerri-Lee |title=Rainbow Sundews |url=https://southernforestlife.net/happenings/2020/8/sundews |website=Life in a Southern Forest|date=August 25, 2020 |access-date=15 March 2022}}</ref>

In South Africa and Australia, two of the three centers of [[species diversity]], the natural habitats of these plants are undergoing a high degree of pressure from human activities.  The African sundews ''[[Drosera insolita|D. insolita]]'' and ''[[Drosera katangensis|D. katangensis]]'' are listed as critically endangered by the  [[International Union for Conservation of Nature]] (IUCN), while ''[[Drosera bequaertii|D. bequaertii]]'' is listed as vulnerable.<ref name="San Diego Zoo"/> Expanding population centers such as [[Queensland]], [[Perth]], and [[Cape Town]], and the draining of moist areas for agriculture and forestry in rural areas threaten many such habitats. The droughts that have been sweeping Australia in the 21st century pose a threat to many species by drying up previously moist areas.<ref name="Cross-2020"/>

Those species endemic to a very limited area are often most threatened by the collection of plants from the wild. ''[[Drosera madagascariensis|D. madagascariensis]]'' is considered endangered in [[Madagascar]] because of the large-scale removal of plants from the wild for exportation; 10 - 200 million plants are harvested for commercial medicinal use annually.<ref name="Baranyai-2016"/><ref name="Cross-2020"/>

== Gallery of prey ==
<gallery>
File:Drosera. Tipulidae.jpg|[[Tipulidae]] (crane fly) trapped by ''Drosera filiformis''
File:Drosera. Phalaenophana.jpg|Moth, ''Phalaenophana pyramusalis'' (Dark-banded Owlet) trapped by ''Drosera filiformis''
File:Drosera. Eusarca confusaria.jpg|''Eusarca confusaria'' moth trapped by ''Drosera filiformis''
File:Drosera. Tabanus ventral.jpg|''Tabanus'' fly trapped by ''Drosera filiformis''
File:Drosophila melanogaster ♀ Melgen, 1830, Drosera capensis Linnaeus, 1753 1100.1.2171.JPG|''Drosophila melanogaster'' fly trapped by ''Drosera capensis''
</gallery>

== Uses ==
The [[corm]]s of the tuberous sundews native to Australia are considered a delicacy by the [[Indigenous Australians]].<ref name="Barthlott-2004"/>{{rp|100}} Some of these corms were also used to dye textiles,<ref name="Yusuf-2017">{{cite journal |last1=Yusuf |first1=Mohd |last2=Shabbir |first2=Mohd |last3=Mohammad |first3=Faqeer |title=Natural Colorants: Historical, Processing and Sustainable Prospects |journal=Natural Products and Bioprospecting |date=16 January 2017 |volume=7 |issue=1 |pages=123–145 |doi=10.1007/s13659-017-0119-9 |pmid=28093670 |pmc=5315675 |issn=2192-2195}}</ref><ref name="Plantarara">Plantarara (2001): [http://www.plantarara.com/carnivoren_information/karnivoren_arzneimittel/carnivorenarznei.htm Artzneimittle, Tee, und Likör aus fleischfressenden Pflanzen] {{Webarchive|url=https://web.archive.org/web/20060618123220/http://plantarara.com/carnivoren_information/karnivoren_arzneimittel/carnivorenarznei.htm |date=2006-06-18 }}</ref> while another purple or yellow dye was [[Traditional dyes of the Scottish Highlands|traditionally prepared]] in the [[Scottish Highlands]] using ''D. rotundifolia''.<ref>Dwelly, Edward; "Dwelly’s [Scottish] Gaelic Dictionary" (1911) (Dath)</ref> A sundew [[liqueur]] is made using fresh leaves from mainly ''[[Drosera capensis|D. capensis]]'', ''[[Drosera spatulata|D. spatulata]]'', and ''D. rotundifolia''.<ref name="Plantarara"/>

===Traditional medicine ===
The [[Zafimaniry]] people in central Madagascar have been using ''[[Drosera madagascariensis]]'' as a remedy for dysentery and fever.<ref>{{cite journal |last1=Rakotondrafara |first1=Andriamalala |last2=Rakotondrajaona |first2=Roland |last3=Rakotoarisoa |first3=Marrino |last4=Ratsimbason |first4=Michel |last5=Rasamison |first5=Vincent Emile |last6=Rakotonandrasana |first6=Stephan Richard |title=Ethnobotany of medicinal plants used by the Zafimaniry clan in Madagascar |journal=The Journal of Phytopharmacology |date=December 2018 |volume=7 |issue=6 |pages=483–494 |doi=10.31254/phyto.2018.7606|doi-access=free }}</ref>

In Western medicine, sundews were used as [[herbal medicine|medicinal herbs]] as early as the 12th century, when an Italian doctor from the School of Salerno, [[Matthaeus Platearius]], described the plant as an herbal remedy for [[cough]]s under the name ''herba sole''.<ref>{{cite web |title=Drosera herba |url=https://www.altmeyers.org/en/naturopathy/drosera-herba-143953 |website=Altmeyers Encyclopedia - Department Phytotherapy |access-date=17 March 2022 |language=en |date=29 October 2020}}</ref> 
Culbreth's 1927 ''Materia Medica'' listed ''D. rotundifolia'', ''D. anglica'' and ''[[Drosera linearis|D. linearis]]'' as being used as [[stimulants]] and [[expectorant]]s, and "of doubtful efficacy" for treating [[bronchitis]], [[whooping cough]], and [[tuberculosis]].<ref name="Culbreth-1927">{{cite book |last1=Culbreth |first1=David M. R. |title=Materia Medica and Pharmacology |date=1927 |publisher=Lea & Febiger |location=Philadelphia}}</ref>  
Sundew tea was recommended by herbalists for dry coughs, [[bronchitis]], [[whooping cough]], [[asthma]] and "bronchial cramps".<ref name="Schilcher-1993">{{cite journal | last1 = Schilcher | first1 = H. | last2 = Elzer | first2 = M. | year = 1993 | title = Drosera (Sundew): A proven antitussive | journal = Zeitschrift für Phytotherapie | volume = 14 | issue = 50| page = 4 }}</ref>
The ''French Pharmacopoeia'' of 1965 listed sundew for the treatment of inflammatory diseases such as asthma, [[chronic bronchitis]] and whooping cough.<ref name="Ghate-2016">{{cite journal |last1=Ghate |first1=N. B. |last2=Das |first2=A. |last3=Chaudhuri |first3=D. |last4=Panja |first4=S. |last5=Mandal |first5=N. |title=Sundew plant, a potential source of anti-inflammatory agents, selectively induces G2/M arrest and apoptosis in MCF-7 cells through upregulation of p53 and Bax/Bcl-2 ratio |journal=Cell Death Discovery |date=2016 |volume=2 |pages=15062 |doi=10.1038/cddiscovery.2015.62 |pmid=27551490 |pmc=4979533 |issn=2058-7716}}</ref>

''Drosera'' has been used commonly in cough preparations in Germany and elsewhere in Europe.<ref>{{cite web |title=Sundew |url=https://wa.kaiserpermanente.org/kbase/topic.jhtml?docId=hn-2171001 |website=Kaiser Permanente |access-date=17 March 2022}}</ref> In [[traditional medicine]] practices, ''Drosera'' is used to treat ailments such as [[asthma]], coughs, lung infections, and [[stomach ulcer]]s.<ref name="Hoffmann-2003">{{cite book |last1=Hoffmann |first1=David |title=Medical Herbalism: The Science and Practice of Herbal Medicine |date=24 October 2003 |publisher=Simon and Schuster |isbn=978-1-59477-890-2 |url=https://books.google.com/books?id=e10oDwAAQBAJ&pg=PT1474 |access-date=17 March 2022 |language=en}}</ref>

Herbal preparations are primarily made using the roots, flowers, and fruit-like capsules.<ref>{{cite book |last1=Wichtl |first1=M. |title=Herbal drugs and phytopharmaceuticals : a handbook for practice on a scientific basis |date=1994 |publisher=CRC Press |location=Boca Raton, FL |isbn= |pages=178, 81 |edition=}}</ref> Since all native sundews species are protected in many parts of Europe and North America, [[extract]]s are usually prepared using cultivated fast-growing sundews (specifically ''D. rotundifolia'', ''[[Drosera intermedia|D. intermedia]]'', ''D. anglica'', ''[[Drosera ramentacea|D. ramentacea]]'' and ''D. madagascariensis'') or from plants collected and imported from Madagascar, Spain, France, Finland and the [[Baltics]].

Sundews are historically mentioned as an [[aphrodisiac]]<ref name="Wolf-2006">{{cite web |last1=Wolf |first1=E. |last2=Gage |first2=E. |last3=Cooper |first3=D.J. |title=Drosera rotundifolia L. (roundleaf sundew): a technical conservation assessment |url=https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5250874.pdf |website=USDA Forest Service, Rocky Mountain Region |access-date=17 March 2022|date=29 June 2006 }}</ref> (hence the common name ''lustwort'').<ref name="Vogel">{{cite web |last1=Vogel |first1=A. |title=Drosera rotundifolia L. {{!}} Round-leafed Sundew |url=https://www.avogel.com/plant-encyclopaedia/drosera_rotundifolia.php |website=Plant Encyclopaedia |access-date=17 March 2022 |language=en}}</ref> They are mentioned as a folk remedy for treatment of warts, corns, and freckles.<ref name="Crowder-1990">{{cite journal |last1=Crowder |first1=A. A. |last2=Pearson |first2=M. C. |last3=Grubb |first3=P. J. |last4=Langlois |first4=P. H. |title=Drosera L. |journal=Journal of Ecology |date=1990 |volume=78 |issue=1 |pages=233–267 |doi=10.2307/2261048 |jstor=2261048 |bibcode=1990JEcol..78..233C |url=https://www.jstor.org/stable/2261048 |access-date=15 March 2022 |issn=0022-0477|url-access=subscription }}</ref>

=== As ornamental plants ===
Because of their carnivorous nature and the beauty of their glistening traps, sundews have become favorite [[ornamental plant]]s; however, the environmental requirements of most species are relatively stringent and can be difficult to meet in cultivation. As a result, most species are unavailable commercially. A few of the hardiest varieties, however, have made their way into the mainstream nursery business and can often be found for sale next to [[Venus flytrap]]s. These most often include ''[[Drosera capensis|D. capensis]]'', ''[[Drosera aliciae|D. aliciae]]'', and ''[[Drosera spatulata|D. spatulata]]''.<ref name="Rice-2006">Rice, Barry. 2006. ''Growing Carnivorous Plants''. Timber Press: Portland, Oregon.</ref>

Cultivation requirements vary greatly by species. In general, though, sundews require high environmental moisture content, usually in the form of a constantly moist or wet soil substrate. Most species also require this water to be pure, as nutrients, salts, or minerals in their soil can stunt their growth or even kill them. Commonly, plants are grown in a soil substrate containing some combination of dead or live [[sphagnum moss]], [[sphagnum]] [[peat moss]], sand, and/or [[perlite]], and are watered with [[Distilled water|distilled]], [[reverse osmosis]], or rain water.<ref name="D'Amato, Peter-1998"/>

=== Nano-biotechnology ===
The mucilage produced by ''Drosera'' has remarkable elastic properties and has made this genus a very attractive subject in biomaterials research. In one recent study, the adhesive mucilages of three species (''D.&nbsp;binata'', ''D.&nbsp;capensis'', and ''D.&nbsp;spatulata'') were analyzed for [[nanofiber]] and [[nanoparticle]] content.<ref name="Zhang-2010">{{Cite journal | doi=10.1186/1477-3155-8-20 | pmid = 20718990 | pmc = 2931452 | title = Nanofibers and nanoparticles from the insect capturing adhesive of the Sundew (''Drosera'') for cell attachment | year = 2010 | author = Zhang, M. | journal = Journal of Nanobiotechnology | volume = 8 | issue = 20 | last2 = Lenaghan | first2 = S.C. | last3 = Xia | first3 = L. | last4 = Dong | first4 = L. | last5 = He | first5 = W. | last6 = Henson | first6 = W.R. | last7 = Fan | first7 = X. | pages=20 | doi-access = free }}</ref> Using [[atomic force microscopy]], [[transmission electron microscopy]], and [[energy-dispersive X-ray spectroscopy]], researchers were able to observe networks of nanofibers and nanoparticles of various sizes within the mucilage residues. In addition, [[calcium]], [[magnesium]], and [[chlorine]] – key components of biological salts - were identified.<ref name="Zhang-2010"/> These nanoparticles are theorized to increase the viscosity and stickiness of the mucilage, in turn increasing the effectiveness of the trap.

More importantly for biomaterials research, however, is the fact that, when dried, the mucin provides a suitable substrate for the attachment of living cells. This has important implications for tissue engineering, especially because of the elastic qualities of the adhesive. Essentially, a coating of ''Drosera'' mucilage on a surgical implant, such as a replacement hip or an organ transplant, could drastically improve the rate of recovery and decrease the potential for rejection, because living tissue can effectively attach and grow on it. The authors also suggest a wide variety of applications for ''Drosera'' mucin, including wound treatment, regenerative medicine, or enhancing synthetic adhesives.<ref name="Zhang-2010"/> Because this mucilage can stretch to nearly a million times its original size and is readily available for use, it can be an extremely cost-efficient source of biomaterial.<ref name="Gaddam-2021">{{cite journal |last1=Gaddam |first1=Susmila Aparna |last2=Kotakadi |first2=Venkata Subbaiah |last3=Subramanyam |first3=Gunasekhar Kalavakunta |last4=Penchalaneni |first4=Josthna |last5=Challagundla |first5=Varadarajulu Naidu |last6=Dvr |first6=Sai Gopal |last7=Pasupuleti |first7=Visweswara Rao |title=Multifaceted phytogenic silver nanoparticles by an insectivorous plant Drosera spatulata Labill var. bakoensis and its potential therapeutic applications |journal=Scientific Reports |date=9 November 2021 |volume=11 |issue=1 |pages=21969 |doi=10.1038/s41598-021-01281-8 |pmid=34753977 |pmc=8578548 |bibcode=2021NatSR..1121969G |url=https://doi.org/10.1038/s41598-021-01281-8 |access-date=17 March 2022 |language=en |issn=2045-2322}}</ref>

==Chemical constituents==
Several chemical compounds with potential biological activities are found in sundews, including [[flavonoid]]s ([[kaempferol]], [[myricetin]], [[quercetin]] and [[hyperoside]]),<ref>{{cite journal | author = Ayuga C | title = Contribución al estudio de flavonoides en D. rotundifolia L | journal = An R Acad Farm | year = 1985 | volume = 51 | pages = 321–326|display-authors=etal}}</ref> [[quinones]] ([[plumbagin]],<ref>{{cite journal | author = Wagner H | title = Immunological investigations of naphthoquinone – containing plant extracts, isolated quinones and other cytostatic compounds in cellular immunosystems | journal = Phytochem Soc Eur Symp | year = 1986 | pages = 43|display-authors=etal}}</ref> [[hydroplumbagin glucoside]]<ref>{{cite journal | pmid = 5774641 | year = 1969 | last1 = Vinkenborg | first1 = J | last2 = Sampara-Rumantir | first2 = N | last3 = Uffelie | first3 = OF | title = The presence of hydroplumbagin glucoside in Drosera rotundifolia L | volume = 104 | issue = 3 | pages = 45–9 | journal = Pharmaceutisch Weekblad}}</ref> and [[rossoliside]] (7–methyl–hydrojuglone–4–glucoside)<ref>{{cite journal | author = Sampara-Rumantir N. | title = Rossoliside | journal = Pharm Weekbl | year = 1971 | volume = 106 | pages = 653–664 | pmid = 5566922 | issue = 35}}</ref>), and other constituents such as [[carotenoid]]s, plant acids (e.g. [[butyric acid]], [[citric acid]], [[formic acid]], [[gallic acid]], [[malic acid]], [[propionic acid]]), [[resin]], [[tannins]] and [[ascorbic acid]] (vitamin C).

== References ==
{{Reflist}}

== Further reading ==
* {{cite book |last1=Barthlott |first1=Wilhelm |last2=Porembski |first2=Stefan |last3=Seine |first3=Rüdiger |last4=Theisen |first4=Inge  |title=The curious world of carnivorous plants : a comprehensive guide to their biology and cultivation |date=2007 |publisher=Timber Press |location=Portland, Or. |isbn=978-0881927924 |edition=English language}} 
* Correa A., Mireya D.; Silva, Tania Regina Dos Santos: ''Drosera (Droseraceae)'', in: Flora Neotropica, Monograph 96, New York, 2005
* Lowrie, Allen: ''[[Carnivorous Plants of Australia]]'', Vol. 1–3, English, Nedlands, Western Australia, 1987–1998
* {{cite journal |last1=Lowrie |first1=A. |title=A taxonomic revision of Drosera section Stolonifera (Droseraceae), from south-west Western Australia |journal=Nuytsia |date=2005 |volume=15 |issue=3 |pages=355–393 |doi=10.58828/nuy00412 |url=https://florabase.dpaw.wa.gov.au/science/nuytsia/412.pdf}}
* Olberg, Günter: ''Sonnentau'', Natur und Volk, Bd. 78, Heft 1/3, pp.&nbsp;32–37, Frankfurt, 1948
* Seine, Rüdiger; Barthlott, Wilhelm: ''Some proposals on the infrageneric classification of Drosera L.'', Taxon 43, 583 - 589, 1994
* Schlauer, Jan: ''A dichotomous key to the genus Drosera L. (Droseraceae)'', Carnivorous Plant Newsletter, Vol. 25 (1996)

== External links ==
{{Wiktionary|Sundew}}
* [https://web.archive.org/web/20080218095109/http://virtuelle.gefil.de/~chrusty/droserakeyeng.htm A key to ''Drosera'' species, with distribution maps and growing difficulty scale]
* [https://web.archive.org/web/20090615075407/http://cpphotofinder.com/Drosera.html A virtually exhaustive listing of ''Drosera'' pictures on the web]
* [http://www.carnivorousplants.org/ International Carnivorous Plant Society]
* [http://www.sarracenia.com/faq.html Carnivorous Plant FAQ]
* [http://www.growsundews.com/ The Sundew Grow Guides]
* [http://www.smugmug.com/search/index.mg?searchWords=drosera&searchType=Image&start=0 Sundew images from smugmug]
* [http://www.botany.org/carnivorous_plants/Drosera.php Botanical Society of America, ''Drosera'' - the Sundews] {{Webarchive|url=https://web.archive.org/web/20100613054559/http://www.botany.org/carnivorous_plants/Drosera.php |date=2010-06-13 }}
{{sister project links|commons=yes|species=drosera|wikt=drosera|n=no|q=no|v=no|s=no|b=no}}
{{CarnivorousPlants}}
{{Taxonbar|from=Q266}}

[[Category:Drosera| ]]
[[Category:Taxa named by Carl Linnaeus]]