{{short description|Feathery part of a seed of a plant in the family Asteraceae}} {{distinguish|Glossary of botanical terms#coma}} {{about|a flower structure|the mathematician|Pappus of Alexandria}} {{redirect|Pappi|the 1934 German film|Pappi (film)}} [[File:Taraxacum - dandelion clock (KK).jpg|thumb|The pappus-clad fruits that make up the familiar "[[Taraxacum officinale|dandelion clock]]" being dispersed by the wind (family [[Asteraceae]])]] [[File:Bidens frondosa 15-p.bot-biden.frondo-21.jpg|thumb|''[[Bidens frondosa]]'' achenes with barbed pappus]]
In [[Asteraceae]], the '''pappus''' is the modified [[calyx_(botany)|calyx]],<ref>{{Cite book |last1=Wunderlin |first1=Richard P. |title=Guide to the vascular plants of Florida |last2=Hansen |first2=Bruce F. |date=2011 |publisher=University press of Florida |isbn=978-0-8130-3543-7 |edition=3rd |location=Gainesville (Fla.) |page=640}}</ref> the part of an individual floret, that surrounds the base of the [[petal|corolla]] tube in [[flower]]. It functions as a dispersal mechanism for the [[achene]]s that contain the seeds.
In Asteraceae, the pappus may be composed of bristles (sometimes feathery), awns, scales, or may be absent, and in some species, is too small to see without magnification. In genera such as ''[[Taraxacum]]'' or ''[[Eupatorium]]'', feathery bristles of the pappus function as a "parachute" which enables the seed to be carried by the wind.<ref>{{cite web | url = https://www.backyardnature.net/fl_comps.htm | title = Composite flowers }}</ref> In genera such as ''[[Bidens]]'' the pappus has hooks that function in mechanical dispersal.
The name derives from the [[Ancient Greek]] word ''pappos'', [[Latin]] ''pappus'', meaning "old man", so used for a plant (assumed to be an ''[[Erigeron]]'' species) having bristles and also for the woolly, hairy seed of certain plants.
The pappus of the [[Taraxacum|dandelion]] plays a vital role in the wind-aided dispersal of its seeds. By creating a [[Vortex ring|separated vortex ring]] in its wake, the flight of the pappus is stabilized and more lift and drag are produced.<ref>{{Cite journal|last1=Cummins|first1=Cathal|last2=Seale|first2=Madeleine|last3=Macente|first3=Alice|last4=Certini|first4=Daniele|last5=Mastropaolo|first5=Enrico|last6=Viola|first6=Ignazio Maria|last7=Nakayama|first7=Naomi|date=2018|title=A separated vortex ring underlies the flight of the dandelion|journal=Nature|volume=562|issue=7727|pages=414–418|doi=10.1038/s41586-018-0604-2|pmid=30333579|bibcode=2018Natur.562..414C|s2cid=52988814|issn=0028-0836|url=https://eprints.gla.ac.uk/171858/7/171858.pdf}}</ref><ref>{{Cite journal|last1=Ledda|first1=P. G.|last2=Siconolfi|first2=L.|last3=Viola|first3=F.|last4=Camarri|first4=S.|last5=Gallaire|first5=F.|date=2019-07-02|title=Flow dynamics of a dandelion pappus: A linear stability approach|journal=Physical Review Fluids|volume=4|issue=7|article-number=071901|doi=10.1103/physrevfluids.4.071901|bibcode=2019PhRvF...4g1901L|issn=2469-990X|hdl=11568/998044|s2cid=198429309 |url=https://research.utwente.nl/en/publications/flow-dynamics-of-a-dandelion-pappus(f98244a1-97b0-4aa2-8a22-bcf113eb8d18).html |hdl-access=free}}</ref> The pappus also has the property of being able to change its morphology in the presence of moisture in various ways that aid germination. The change of shape can adjust the rate of [[abscission]], allowing increased or decreased germination depending on the favorability of conditions.<ref>{{Cite journal|last=Greene|first=David F.|date=2005|journal=Ecology|volume=86|issue=11|pages=3105–3110|doi=10.1890/04-1430|issn=0012-9658|title=The Role of Abscission in Long-Distance Seed Dispersal by the Wind|bibcode=2005Ecol...86.3105G }}</ref><ref>{{cite journal |last1=Seale|first1=Madeleine|last2=Zhdanov|first2=Oleksandr|last3=Cummins|first3=Cathal|last4=Kroll|first4=Erika|last5=Blatt|first5=Michael R|last6=Zare-Behtash|first6=Hossein|last7=Busse|first7=Angela|last8=Mastropaolo|first8=Enrico|last9=Viola|first9=Ignazio Maria|title=Environmental morphing enables informed dispersal of the dandelion diaspore |journal=eLife |date=2022 |volume=11 |article-number=e81962 |doi=10.7554/eLife.81962 |doi-access=free |biorxiv = 10.1101/542696}}</ref>
==Biomimicry== The pappus of the dandelion has been studied and reproduced for a variety of applications. It has the ability to retain about 100 times its weight in water and pappus-inspired mechanisms have been proposed and fabricated which would allow highly efficient and specialized liquid transport.<ref>{{Cite journal|last1=Meng|first1=Qingan|last2=Wang|first2=Qianbin|last3=Liu|first3=Huan|last4=Jiang|first4=Lei|date=2014|title=A bio-inspired flexible fiber array with an open radial geometry for highly efficient liquid transfer|journal=NPG Asia Materials|volume=6|issue=9|pages=e125|doi=10.1038/am.2014.70|issn=1884-4049|doi-access=free}}</ref> Another application of the pappus is in the use of [[Air flow meter|minute airflow detection]] around walls which is important for measuring small fluctuations in airflow in neonatal incubators or to measure low velocity airflow in heating and ventilation systems.<ref>{{Cite journal|last1=Bruecker|first1=Christoph H.|last2=Mikulich|first2=Vladimir|date=2017-06-28|title=Sensing of minute airflow motions near walls using pappus-type nature-inspired sensors|journal=PLOS ONE|volume=12|issue=6|article-number=e0179253|doi=10.1371/journal.pone.0179253|pmid=28658272|pmc=5489159|bibcode=2017PLoSO..1279253B|issn=1932-6203|doi-access=free}}</ref>
==References== {{Reflist}}
==External links== * [https://web.archive.org/web/20061012095329/http://www.botany.utoronto.ca/courses/BOT307/Carr-vascular/senecioneae.htm Asteraceae morphology] * [https://www.backyardnature.net/fl_comps.htm Composite flowers] *[[Biomimetics]]
[[Category:Plant morphology]] [[Category:Asteraceae]]