Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

, the pappus is the modified calyx, the part of an individual floret, that surrounds the base of the corolla tube in

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

. It functions as a dispersal mechanism for the

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple fruit, simple dry fruits, dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and Dehi ...

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 ''Taraxacum'' () is a genus of flowering plants in the family Asteraceae, which consists of species commonly known as dandelions. The scientific and hobby study of the genus is known as taraxacology. The genus has a near-cosmopolitan distribu ...

'' or '' Eupatorium'', feathery bristles of the pappus function as a "parachute" which enables the seed to be carried by the wind. In genera such as '' Bidens'' the pappus has hooks that function in mechanical dispersal. The name derives from the

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

word ''pappos'',

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''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

dandelion ''Taraxacum'' () is a genus of flowering plants in the family Asteraceae, which consists of species commonly known as dandelions. The scientific and hobby study of the genus is known as taraxacology. The genus has a near-cosmopolitan distribu ...

plays a vital role in the wind-aided dispersal of its seeds. By creating a separated vortex ring in its wake, the flight of the pappus is stabilized and more lift and drag are produced. 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 Abscission () is the shedding of various parts of an organism, such as a plant dropping a leaf, fruit, flower, or seed. In zoology, abscission is the intentional shedding of a body part, such as the shedding of a claw, husk, or the autotomy of a ...

, allowing increased or decreased germination depending on the favorability of conditions.

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. Another application of the pappus is in the use of 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.

References

{{Reflist

External links

Asteraceae morphology

*

Biomimetics Biomimetics or biomimicry is the emulation of the models, systems, and elements of nature for the purpose of solving complex human problems. The terms "biomimetics" and "biomimicry" are derived from (''bios''), life, and μίμησις (''mimes ...

Plant morphology Asteraceae