Fruits

A true fruit is derived solely from the carpel or carpels of a flower after pollination. Some fruits are juicy, but many others are dry when they are ripe and they split open to release their seeds. Pea and bean pods are examples although we eat some of them before they are ripe. Botanists split juicy fruits into several groups. Berries generally have many seed embedded in the soft flesh. Grapes, gooseberries and citrus fruits are familiar examples.
The fruit and vegetables that we eat contain starch, sugar and other foodstuffs that the plants have stored up for their own use. Botanically speaking, fruits are formed from the pollinated flowers of plants. They always contain seeds. The term vegetable is generally used in amore loose way, often simply referring to plants eaten with the main course of the meal. This can cause some confusion. Cucumbers, marrows, peppers and tomatoes are commonly considered vegetables, although to the botanist they are in fact fruits.
Almost juicy fruits are rich in sugar and therefore quite sweet when they are ripe. Some also store starch and oils. These food reserves are not consumed by the plants themselves, but serve to attract animals that eat the flesh and scatter the seed. Most commercial fruits are obtained from trees and shrubs, although some important one, such as strawberries and pineapples, come from herbaceous plants. A few fruits are still gathered mainly from the wild, but the majority is now cultivated in plantations or orchards and, as with the vegetables, many are now larger and tastier than their ancestral forms.

Nuts

Botanically speaking, a nut is a dry fruit containing a single seed and having a hard, woody outer coat. Hazelnuts and sweet chestnuts are true nuts, and so are cashews and macadamia nuts, but in fact most of the other “nuts” that we buy in the shops are not nuts at all. They are mostly the inner parts of other kinds of fruits.

Walnuts, pecans and almonds, for example, are the equivalents of peach or plum stones, and until they fall from the trees they are enclosed in tough, leathery cases that correspond to the flesh of the peach or plum. Even the hard shelled coconuts are also the inner parts of the fruit, although here the outer part is thick and fibrous – it is used for coconut matting. Brazil nuts are actually hard shelled seeds that are obtained from ball shaped woody fruits.

Ground nuts or peanuts are the seeds of a leguminous plant, carried in pods. In all these examples, the parts that we actually eat are the seeds or kernels- the embryonic next generation of plants and their food reserves.

Unusual Adaptation

Flowering plants have evolved in many directions, becoming adapted to a wide range of habitats and acquiring many life styles. Plants growing on high mountains or on the northern tundra usually form mats or cushions close to the ground to escape the violent winds. The dwarf willow Salix herbacea, for example is a true willow, but it has underground stems and its aerial branches are rarely more than 3cm above the ground. The leaves and flowers of many mountain plants are darker than those of their low land relatives; dark colours absorb heat more efficiently in the cold climate.

Many plants manage to live in deserts despite the scarcity of water. Some of them are quick growing annuals that complete their life cycles in a short time and are not affected by the drought, but the typical desert plants store water through the dry season. Waxy or hairy coatings, and breathing pores sunk in deep grooves ensure that evaporation is cut to minimum. Many of the plants have very small leaves or none at all, although some species sprout leaves when the rains come and then drop them for the dry season.

Cacti nearly all grow in the American deserts and can survive prolonged drought. They have no proper leaves and their ribbed grooves store all their food. Wide spreading roots catch nearly all the rain that falls in the wet season and the stems swell up as they take up water. The stems shrink as they use up water in the dry season, and the grooves become deeper. The breathing pores in the grooves thus become better protected from the dry air. Spines protect the cacti from grazing animals seeking moisture.