The Invisible Colours of Flowers

Three handouts were available,

Determining flower structure.

How many of us have wondered at the variety of shapes and structures in a collection of beautiful blooms? The diversity is especially striking when we consider that flowers are typically made up of four basic parts - the outermost sepals surrounding the petals, then the stamens and finally one or more central carpels.......read entire handout.

Determining flower symmetry.

In 1742 the famous botanist, Carolus Linnaeus, found a remarkable toadflax plant on an island near Stockholm. Normal toadflax (Linaria vulgaris) flowers have distinctive upper and lower petals but, in this specimen, the petals all looked the same, making the flower radially symmetrical. Linnaeus was the founding father of plant and animal classification. His classification system for plants was based on flower structure, and so the unusual toadflax should have belonged to a totally new species. Yet, in every other respect, it resembled common toadflax. Linnaeus concluded that this peculiar plant had arisen by the “transformation” of common toadflax into a new species - a radical idea at a time when species were thought to be fixed, timeless acts of creation. Even though the flowers themselves were quite attractive, he named the new form Peloria, Greek for ‘monster’, because the disturbing biological implications of their discovery made them monstrous. ......read entire handout

Gene switches.

A mature plant is a remarkably complex structure compared with the single fertilised egg cell from which it develops. The single egg cell, and the plant embryo it soon becomes, must gradually establish a set of complex patterns, such as those required to form leaves and flowers, for example. These patterns must be established at the correct time and place in the plant, for the flower to develop properly.......read entire handout.