Editing Dipsacus (section)

==Description==
Teasels are easily identified with their prickly stem and leaves, and the [[inflorescence]] of purple, dark pink, lavender or white [[flower]]s that form a head on the end of the stem(s). The inflorescence is ovoid, {{Convert|4|–|10|cm|in}} long and {{Convert|3|–|5|cm|in}} broad, with a basal whorl of spiny [[bract]]s. The first flowers begin opening in a belt around the middle of the spherical or oval flowerhead, and then open sequentially toward the top and bottom, forming two narrow belts as the flowering progresses. The dried head persists afterwards, with the small ({{Convert|4|–|6|mm|in|adj=on}}) [[seed]]s maturing in mid autumn. In rainy weather, some seeds may germinate when still in the seedhead ([[vivipary]]).

[[File:Dipsacus-fullonum-Teasel-seedhead-w-viviparous-germination-PortSunlightRiverPark-UK-23Oct2019.jpg|thumb|Infructescence of ''Dipsacus fullonum'' (common teasel) showing seeds germinating while still in infructescence (vivipary).]]

===Carnivory===
[[Carnivorous plant|Carnivory]] in teasels was discussed by [[Francis Darwin]] (son of [[Charles Darwin]]) in a paper held by the [[Royal Society]].<ref>{{Cite web |date=2020-11-27 |title=Dipsacus and Drosera: Frank's favourite carnivores |url=https://www.darwinproject.ac.uk/commentary/life-sciences/dipsacus-and-drosera-frank-s-favourite-carnivores |access-date=2023-09-28 |website=Darwin Correspondence Project |language=en}}</ref><ref>Mentioned in episode of {{Citation|last=Objectivity|title=White Gloves of Destiny (Random Researcher) - Objectivity #72|date=2016-05-31|url=https://www.youtube.com/watch?v=wms6s2AWcbk |archive-url=https://ghostarchive.org/varchive/youtube/20211212/wms6s2AWcbk| archive-date=2021-12-12 |url-status=live|access-date=2016-05-31}}{{cbignore}}</ref>

Rain water can collect in the cup-like receptacles that form where sessile leaves join the stem; this structure may perform the function of preventing sap-sucking [[insect]]s such as [[aphid]]s from climbing the stem. These in turn may also be used to collect the [[nutrients]] from any animal matter that accumulates within them, making them a form of [[protocarnivorous plant]].

Contemporary attempts to replicate Darwin's experiments on the common teasel continue to fuel debate over whether or not ''Dipsacus'' is truly carnivorous. A 2011 study revealed increased seed production (but not height) dependent on both amount and nature of introduced animal supplementation, while 2019 experiments suggested that the increased seed set was a response to poor soil conditions rather than proof of proto-carnivory.<ref>{{cite journal|last1=Shaw|first1=P. J. A.|last2=Shackleton|first2=K.|editor1-last=Joly|editor1-first=Simon|doi=10.1371/journal.pone.0017935|title=Carnivory in the teasel ''Dipsacus fullonum'' — the effect of experimental feeding on growth and seed set|journal=PLOS ONE|volume=6|issue=3|pages=e17935|year=2011|pmid=21445274|pmc=3060873|bibcode=2011PLoSO...617935S|doi-access=free}}</ref><ref>Krupa, James J., and J. Matthew Thomas. "Is the Common Teasel (''Dipsacus Fullonum'') Carnivorous or Was Francis Darwin Wrong?" ''Botany'' 97, no. 6 (March 22, 2019): 321–28. {{Doi|10.1139/cjb-2019-0008}}.
</ref> The [[leaf shape]] is lanceolate, {{convert|20|-|40|cm|in}} long and {{convert|3|–|6|cm|in}} broad, with a row of small spines on the underside of the midrib.

===As food===
The seeds are an important winter food resource for some [[bird]]s, notably the [[European goldfinch]]. Teasels are often grown in [[garden]]s and encouraged on some [[nature reserve]]s to attract them.<ref>
{{Cite web
|url=http://www.rspb.org.uk/wildlife/birdguide/name/g/goldfinch/garden.aspx
|title=Advice from the Royal Society for the Protection of Birds on how to attract Goldfinch to your garden with teasel
|access-date=October 16, 2011
}}</ref>

===As an invasive species===
[[Image:Dipsacus laciniatus.JPG|thumb|right|A stand of cut-leaved teasel]]

Teasel is considered an [[invasive species]] in the United States. It is known to form a monoculture, capable of crowding out all native plant species, and therefore is discouraged or eliminated within restored open lands and other conservation areas.<ref>
{{Cite web
|url=https://www.invasivespeciesinfo.gov/profile/common-teasel
|title=Invasive Species: Plants – Common Teasel (''Dipsacus fullonum'')
|access-date=October 16, 2011
}}</ref><ref>
{{Cite web
 |url=http://dnr.wi.gov/invasives/fact/teasel_com.htm 
 |title=Invasive Species – Common Teasel (''Dipsacus fullonum'' subsp. ''sylvestris'') 
 |access-date=October 16, 2011 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20111112171202/http://dnr.wi.gov/invasives/fact/teasel_com.htm 
 |archive-date=November 12, 2011 
}}</ref><ref>
{{Cite web
 |url         = http://mdc.mo.gov/landwater-care/plant-management/invasive-plant-management/cut-leaved-and-common-teasel
 |title        = Common and Cut-Leaved Teasel Control
 |access-date  = October 16, 2011
 |url-status      = dead
 |archive-url  = https://web.archive.org/web/20110712184815/http://mdc.mo.gov/landwater-care/plant-management/invasive-plant-management/cut-leaved-and-common-teasel
 |archive-date = July 12, 2011
}}</ref> Two moths useful for [[biological control]] were tested in [[Slovakia]] in 2003–2004, including the [[monophagous]] ''[[Endothenia gentianaeana]]'', but the USDA has not approved either of them for introduction as of February 2018. Instead, the USDA continues to suggest the use of herbicidal chemicals.<ref>{{cite book |last1=Sforza |first1=R. |last2=Bon |first2=M. C. |date=2008 |title=Proceedings of the XII International Symposium on Biological Control of Weeds |url=https://books.google.com/books?id=c_cCwli1NQcC&q=%22biological+control%22+teasel&pg=PA216 |publisher=CAB International |pages=216–218 |isbn=978-1-84593-506-1 }}</ref>