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ALL ABOUT FLOWERS

a scent and supply of nectar. Its sole purpose is to ensure the pollination of the ovules con- tained inside the ovary so that fertile seeds can be formed. Pollen from one plant must be trans- ferred to a different plant of the same species in order to fertilize the ovule, which then devel- ops into the seed. Once pollination occurs, the flower can wither away; everything apart from the seed pod shrivels and the seeds continue their development inside a seed pod. Annual plants, which complete their life cycles in the space of one year, will die away completely, leaving only their seeds to survive the winter. Inorder to transfer thepollen fromone flower to another, plants have evolved an immense range of shapes, sizes, colors and scents in their flower structures; these are primarily designed to attract pollinating insects, which are tempted to visit the flower by the prospect of a meal of nectar, and, in the process, become dusted with pollen. The pollen itself is a source of food for many species and is carried away in large quantities by bees that have specially formedpollenbasketsontheir legstohelpthem. When they visit the next flower, the pollen is

Inorder to surviveaplantmusthave light,water, nutrients and space to grow in. It will probably need soil, but some plants are capable of growing on the trunks of trees, floating inwater, or surviv- ing in crevices in rocks. In order to get sufficient light, plants compete with each other by growing taller or by spreading out to take up more room. The plant may also have to protect itself in some way by growing protective spines or having an unpleasant taste. Once the basic needs for lift are satisfied and the plant can produce food and grow successfully, it is able to reproduce itself. This is where the flowers become important. The Structure of the Flower Plants do not produce elaborate flowers just for humans to admire. A considerable effort is put into the production of the flower, which may be a large and complicated structure and often has

Look deep inside the flower and the important struc- tures which help its reproduction will be revealed. Inside the circle of petals is a ring of anthers which release a fine dust of yellow pollen grains. Inside this lies the stigma, the female part of the flower, which receives pollen from anoth- er plant before producing seeds.

The banana passion- flower (Passiflora mollissima) of Colom- bia, is pollinated by hummingbirds that cannot help but be dusted with pollen as they probe their beaks down into the base of the flow- ers for a drink of nectar. The anthers and the stigma are close together, so that pollen stuck to the head of the hummingbird will be transferred to the stigma of the next flower it visits.

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