Investigating the Structure of the Flower

Charles Buzek                  John Spry School
                               2300 S. Marshall
                               Chicago IL 60623
                               (773) 534-1400

Objectives:

    The student will learn the basic anatomy of a flower by means of creating a 
model.
    The student will understand the proportional relationships of the various
parts illustrated.
    The student will understand the value of modeling for learning purposes.

Materials Needed:

    Two sticks of clay
    Toothpicks
    Two sheets of construction paper-red and green

Strategy:

    Though flowers come in many varieties there are types that have both male 
and female sex organs on the same flower.  These types are called perfect 
flowers.  We can construct a model of a perfect flower with the above-mentioned 
materials.  We start with a stick of clay which we use to fashion the stem.  The 
stem will need to support the flower itself and will therefore need to be strong 
enough to support the structure.  So don't stint on the amount of clay, use the 
entire stick to make the stem.  Once done we need to cut out the sepals from the 
green paper.  The sepals were the bud cover while the flower was developing.  
When the flower opened the sepals are pushed back and begin to shrink since they 
no longer function as part of the living flower.  The sepals should be no larger 
than one-fourth the size that the petals will be for your model.  Start by 
drawing a circle the size of the stem, this will be cut-out later.  Around this 
circle draw a four-pointed star.  This forms the sepals and when the circle is 
cut out it will fit over the top of the clay stem.  Push the sepals down about 
one-half inch on the stem. 
    Now cut out from the red sheet the figure which will represent the petals of 
your flower.  Again, as mentioned above, the petals need to be larger than the 
sepals.  The ratio should be about 4 to 1.  The petals serve as a type of 
container for the sexual organs of the plant, attractant of insects, and landing 
strip for the insects.  The number of petals is specific for each floral genus 
so you are free to decide how many petals you want.  As in the case of the  
sepals you must start with a circle the size of the stem.  Once the petals are 
cut out, followed by the circle, fit them over the stem so that they rest on top 
of the sepals leaving a knob of clay. 
    The knob of clay will serve as a platform for the structures that we will 
now fashion.  These structures are the stamen and the pistil.  Beginning with 
the latter we will knead the clay into a shape that resembles a bowling pin. 
Since we are emphasizing these features they may be slightly exaggerated in 
size.  Thus the pistil may be the size of your petals.  The shape of the pistil 
is a case of form following function.  The top portion of the structure is a 
landing platform for pollen.  The enlarged base contains the ovules that sperm 
from the pollen will eventually fertilize. 
    Since nature usually prefers to avoid self-pollination the next structure, 
the stamen, should be modeled smaller in size than the pistil.  It consists of 
the anther, which is the production site of the pollen, and its support, the 
filament.  The latter is made with a toothpick, though for large-scaled models a 
drinking straw may be used.  The anther should be a third to half the size of 
the filament.  Its shape is much like an elongated kidney bean.  The stamen 
should be grouped around the pistil, a suggested number could be six. 

Performance Assessment:

    Any type of modeling activity requires a high degree of concentration and a 
considerable return on the effort is a reasonable expectation.  Consequently 
students can be tested on their acquired knowledge by having them make a drawing 
of a flower based entirely on memory.  The drawing should be correctly labelled.  
One might give a possible number of five quality points based on their drawing 
and nine points for the flower parts for a total of fourteen points.