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Flower Morphology Exercise
You are already familiar with a number of aspects of the vegetative structure of angiosperms from your previous laboratory work. Now you will concentrate on flower structure, since these are the parts of the plant that are most closely associated with sexual reproduction, and are widely used in the classification of the angiosperms.
We know almost nothing about the origin(s) of the angiosperms. They are found in considerable numbers and great variety in fossils from the Cretaceous, and many of the families can be recognized as members of our modern ones. Because of the diversity of the Cretaceaous fossils, it has been suggested that the prior history must be fairly long, but only one or two possible angiosperm remains have been found in earlier geological periods. In a slab of limestone from the Yixian Formation northeast of Beijing, China botanists discovered the earliest angiosperm fossil yet found. Archaefructus (ancient fruit) is 122 to 145 million years old and so it lived in the Jurassic. It is by far the oldest angiosperm found so far. Today over 250,000 species are recognized, and the angiosperms include the principal plants covering the land surface and provide the great majority of the plants used for a variety of economic purposes.
Dissecting Kalanchoe blossfeldianaflowers
These flowers may demonstrate some fusion among flower parts. When the parts of one whorl are fused to each other, this is called connation. In the flower formula, this is represented by a curved line over the number of connate parts. When the parts of two different whorls are fused to each other, this is called adnation. In the flower formula, this is represented by a square bracket beneath and extending between the numbers of parts in the two adnate whorls.Note: one floral feature that this flower may present is a stamen that lacks an anther (not by virtue of it falling off…there just never was one); this is called a staminode (or sometimes staminodium). If staminodia are present, count them as if they were a second kind of stamen (i.e.: x + y in the flower formula).
What is the symmetry of the flower?radialbilateral
Are both calyx and corolla present? yesno
The sepals are:freeconnate. The petals are:freeconnate.
The stamens and staminodes are:freeadnate. The pistils are: freeadnate.
How many sepals are there? ______Petals? ______Stamens? _____ Pistils?_____
If one, the pistil is:simplecompound.
If compound, of how many carpels is the pistil composed? ______
The ovary is: superiorinferior.
The flower is:hypogynousperigynousepigynous.
How many ovules are there? onelessthan20many
Where is/are the placenta(e) to which they are attached? axileradial“marginal”
Give the complete flower formula for your flower (8 pts): ______
Dissecting Pelargonium (Geranium)flowers
Examine one of the flowers provided; draw and label the flower below to show all parts and their relation to one another. Then answer the following questions about the geranium.
What is the symmetry of your geranium flower (look closely!)? radialbilateral
Are both calyx and corolla present?yesno
The sepals are: freeconnate. The petals are: freeconnate.
The stamens are: freeconnateadnate.
Where are the stamens in relation, to the sepals and petals?
One per: perianthpartsepalpetal.
Stamens relatively positioned: interioradjacentexterior.
How many sepals are there? _____ Petals? ______Stamens? ______Pistils?_____
If one, the pistil is simplecompound.
If compound, of how many carpels is the pistil composed? ______
I determined this by counting the number of ______.
The ovary is: superiorinferior.
The flower is:hypogynousperigynousepigynous.
Give the complete flower formula for your flower (8 pts): ______
Diagram and label your flower in the space provided below. Use as many structure name labels as possible based upon the description on pages 1 and 2 (16 labels required).
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Dissecting Viola or Antirrhinumor Phaseolusflowers
The flower of these generashow an apomorphy of strong bilateral symmetry. Such flowers are referred to as zygomorphic or irregular.
What is the symmetry of your ______(genus)flower? radialbilateral
Are both calyx and corolla present? yesno
The sepals are: freeconnate. The petals are: freeconnate.
The stamens are: freeconnateadnate.
How many sepals are there? _____ Petals? ______Stamens? ______Pistils?_____
If one, the pistil is simplecompound.
If compound, of how many carpels is the pistil composed? ______
The ovary is: superiorinferior.
The flower is: hypogynousperigynousepigynous.
How many ovules are there? onelessthan20many
Where is/are the placenta(e) to which they are attached? axileradial“marginal”
Give the complete flower formula for your flower (8 pts): ______
Dissecting Euphorbiamilii(or E. triangularis)flowers
Not everything is the way that it at first seems; ‘Crown of Thorns’ flowers are famously tricky! They often have a showy structure that is not a flower part; a showy leaf is known as a bract. These flowers are also famous for having large nectaries. The combination of nectariesand flowers is called a cyanthium in this group. As an advanced flower, there is much of division of labor and reduction of flower parts. You may need to dissect several to make sense of these!
How many of the accessory structures are shown?____ bracts and ____ nectaries
Use a dissection scope and fine forceps to reveal what is interior to the accessories.
Is what you find the parts of a single flower or many flowers?flowerinflorescence
The perianth(calyx and corolla)is:reducedtoridgesshowy.
The stamens are: individualmultiple. Thesimplecompound pistils have____ carpels.
The ovary is: superiorinferior, so its flower is:hypogynousperigynousepigynous.
How many ovules would be in the gynoecium? onelessthan20many
Give the complete flower formulae (10 pts): Male:______Female:______
You may ignore the symmetry symbol (kind of meaningless here, right?)!
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Dissecting Begoniaxbenariensis‘Big Red’ flowers
Examine the flowers provided; draw and label the flowers below to show all parts and their relation to one another. Then answer the following questions about begonia flowers. Note: begonia flowers introduce a new concept: the bract. This is a leaf associated with the flower that is not part of the flower (neither sepal nor petal, etc.) in spite of its color! Bracts are not part of a flower formula. These flowers also show us that sometimes the perianth is incomplete; in this case the showy perianth parts could be sepals OR petals, so we use tepal as a “hedged” name. In the flower formula there is only one entry for the perianth and after the number you put a T to indicate tepals. Also do not forget that a 0 needs to go into the right place in a flower formula depicting a flower lacking any other whorl!
Begonia flowers are:perfectimperfect. Their perianths are: completeincomplete.
The tepals are: freefused. How many are in male _____ and female _____ flowers?
How many stamens are in a male flower? _____
How many pistils (≠carpels) are in the female flower?_____
When present, the pistil issimplecompound.
If compound, of how many carpels is the pistil composed? ______
I determined this by counting the number of:______and ______.
The ovary is: superiorinferior.
The flower is: hypogynousperigynousepigynous.
Give the complete flower formulae for your begonia flowers (10 pts):
Male:______and Female:______
Diagram and label your flowers in the space provided below. Name the major parts visible in the flowers (8 points)
Male FlowerFemale Flower
stamen-style/stigma-
tepal-tepal-
pedicel-ovary-
bract-
pedicel-