InAsteraceae, thepappus is the modifiedcalyx,[1] the part of an individual floret, that surrounds the base of thecorolla tube inflower. It functions as a dispersal mechanism for theachenes 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 asTaraxacum orEupatorium, feathery bristles of the pappus function as a "parachute" which enables the seed to be carried by the wind.[2] In genera such asBidens the pappus has hooks that function in mechanical dispersal.
The name derives from theAncient Greek wordpappos,Latinpappus, meaning "old man", so used for a plant (assumed to be anErigeron species) having bristles and also for the woolly, hairy seed of certain plants.
The pappus of thedandelion plays a vital role in the wind-aided dispersal of its seeds. By creating aseparated vortex ring in its wake, the flight of the pappus is stabilized and more lift and drag are produced.[3][4] 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 ofabscission, allowing increased or decreased germination depending on the favorability of conditions.[5][6]
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.[7] Another application of the pappus is in the use ofminute 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.[8]
^Wunderlin, Richard P.; Hansen, Bruce F. (2011).Guide to the vascular plants of Florida (3rd ed.). Gainesville (Fla.): University press of Florida. p. 640.ISBN978-0-8130-3543-7.
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