Aster Fruits (Fruit,
Seed, Beak, Pappus, Receptacle)
The Aster Family has
composite flowers (many small florets packed tightly together). When a floret is pollinated, its ovary starts
growing into a fruit. Aster fruits are dry and contain a single seed
enclosed in a thin, dry skin.
Once pollinated, based
in its species genetic code, fruit cells start dividing in complex ways,
creating a new individual. In many
cases, maturing aster fruit grows a beak and pappus that will catch the wind
when the time is right.
Common Dandelion – photo courtesy Keir Morse
The beak is an
extension of the fruit, a narrow column sometimes longer than the fruit itself. At the tip of the beak grows a
species-specific pattern of bristles and/or scales, called pappus.
Horned Dandelion – photo courtesy Steve Matson
Fruit designs
vary. Some have no beaks. Some have a pappus of several scales tipped
by bristles. Others have a pappus of 50
or so hair-like bristles with no scales.
Fruits connect to a receptacle,
which connects to the stem. In this
picture, many of the fruits have already fallen off, showing the underlying
receptacle.
Bigflower Dandelion – photo courtesy Stave Matson
Want more? See Dandelion
Flower Heads and Wikipedia.
Corrections/Comments:
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