pappus


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Related to pappus: Pappus of Alexandria

pap·pus

(pap'ŭs),
The first downy growth of beard.
[G. pappos, down]

pappus

(păp′pŭs) [L.]
The first growth of beard hair appearing on the cheeks and chin as fine, downy hair.

pappus

a circle of hairs formed from a modified CALYX found on the seeds of plants of the family Compositae, for example dandelion and thistle seeds. The pappus assists in the dispersal of the seeds by wind, acting as a kind of parachute.
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References in periodicals archive ?
Some scholars have provided evidence about the specific adaptations (e.g., wing or pappus) for dispersal of early colonizers [54-56].
Of course, students might prefer to use Pappus' Dual Theorem.
Mature plants can produce more than 1000 flower heads with the potential to yield 25000 seeds with pappus, which allows them major wind dispersal (Vigna and Lopez, 2008).
However, Descartes favors his algebra as more transparent (it provides clearer access to how the conclusion is generated), more general (since applicable to several kinds of problems) and heuristically more powerful (it allowed Descartes to find solutions to problems that had baffled ancient geometers such as Pappus' four-line locus problem).
For instance, in his commentary on Book V of Ptolemy's Almagest, Pappus of Alexandria gave a description of this instrument.
Should the hairy crown become wet at the time of its opening, the hydroscopic pappus cannot spread apart the thistle-filaments needed to increase the disseminule's aerodynamic profile.
Species with pappi were anchored by pressing the seed tips in the sand, leaving most of the seed and the pappus exposed.