| PART I. | ||
| The Life of the Plant | ||
| CHAP. | PAGE | |
| I. | Introductory | [1] |
| II. | Signs of Life | [4] |
| III. | Seeds and Seedlings | [8] |
| IV. | Food Materials of the Older Plant—1. In the Soil | [14] |
| V. | Food Materials of the Older Plant—2. In the Air | [18] |
| VI. | The Food Manufactured by the Plant | [23] |
| VII. | The Circulation of Water | [28] |
| VIII. | Light and its Influences | [35] |
| IX. | Growth in Seedlings | [40] |
| X. | Movement | [45] |
| Summary of Part I. | [49] | |
| PART II. | ||
| The Parts of a Plant’s Body, and their Uses | ||
| XI. | Roots | [53] |
| XII. | Stems | [58] |
| XIII. | Leaves | [64] |
| XIV. | Buds | [72] |
| XV. | Flowers | [78] |
| XVI. | Fruits and Seeds | [86] |
| XVII. | The Tissues Building up the Plant Body | [92] |
| PART III. | ||
| Specialisation in Plants | ||
| XVIII. | For Protection against Loss of Water | [99] |
| XIX. | Specialisation for Climbing | [104] |
| XX. | Parasites | [109] |
| XXI. | Plants which eat Insects | [114] |
| XXII. | Flower Structures in Relation to Insects | [118] |
| PART IV. | ||
| The Five Great Classes of Plants | ||
| XXIII. | Flowering Plants | [125] |
| XXIV. | The Pine-Tree Family | [127] |
| XXV. | Ferns and their Relatives | [133] |
| XXVI. | Mosses and their Relatives | [138] |
| XXVII. | Algæ and Fungi | [141] |
| PART V. | ||
| Plants in their Homes | ||
| XXVIII. | Hedges and Ditches | [145] |
| XXIX. | Moorland | [153] |
| XXX. | Ponds | [159] |
| XXXI. | Along the Shore | [165] |
| XXXII. | In the Sea | [173] |
| XXXIII. | Plants of Long Ago | [178] |
| XXXIV. | Physical Geography and Plants | [182] |
| XXXV. | Plant Maps | [188] |
| XXXVI. | Excursions and Collecting | [194] |
| Index | [197] | |
PART I.
THE LIFE OF THE PLANT
CHAPTER I.
INTRODUCTORY
Many people do not realise that plants are alive. This mistake is due to the fact that plants are not so noisy and quick in their ways as animals, and therefore do not attract so much attention to themselves, their lives, and their occupations.
When we look at a sunflower, surrounded by its leaves and standing still and upright in the sunlight, we do not realise at first that it is doing work; we do not connect the idea of work with such a thing of beauty, but look on it as we should on a picture or a statue. Yet all the time that plant is not only living its own life, but is doing work of a kind which animals cannot do. Its green leaves in the light are manufacturing food for the whole plant out of such simple materials that an animal could not use them at all as food. Even its beautiful flower is creating and building up the seeds which will form the sunflowers of the future. All animals directly or indirectly make use of the work done by plants in manufacturing food, for they either live on plants themselves, or eat other animals which do so.
Plants are living, and therefore require food of some kind as well as air and water in the same way, and for the same purposes as do animals. As a rule, we cannot see them breathing and eating, but that is because we do not look in the right way. In our study of plants we must first learn how to see and question them properly, and when we have done this they will show themselves to us and tell us stories of their lives which are quite as interesting as any animal stories.
Now the sunflower we have just thought of is probably growing in a garden well looked after by a gardener, who sees that it gets all the light and water and just the kind of soil it needs. It is therefore protected and cared for to a certain extent, but who looks after the wild plants which manage to grow everywhere? These have not only their own lives to live, but by their own efforts must overcome difficulties which are not even felt by the cultivated ones.
They succeed in a wonderful way, and some plants manage to grow under very difficult conditions, even in places where they get no water for months under a burning sun, or in forests where the overshadowing trees cut off the light and rain, or under the water where they get no direct air. They have to do all the usual work of plants, and at the same time struggle against the hardships of their surroundings. They are like men fighting for their lives with one hand and doing a piece of work with the other.
The result of this is that they sometimes make themselves strange-looking objects, and in some plants which have had a very hard struggle it is difficult to know which part of the plant is which. Look, for example, at a Cactus (see fig. 48), which grows in the desert; it appears to have neither stem nor leaves like an ordinary plant, and to consist merely of a roundish green mass covered with needle-like prickles. Yet when you come to study the Cactus you will find out that the thick, fleshy mass is really its stem, and the prickles its leaves which have taken on these strange shapes. By means of its unusual form the Cactus can live where our common plants would die of the dry heat in a day or two. The power plants have of changing their bodies so as to fit themselves to live under all kinds of conditions is one of the strongest proofs that they are alive.