Compositæ or Carduaceæ—The daisy family and the largest and most complex of all the plant families. As the culmination of the scheme of plant classification, they show the greatest perfection in the arrangements for cross-fertilization. For a description of their flower structure, see Chapter I, page 44, and Figures 43-45. Some of the Compositæ have no ray flowers, others are all ray flowers, but the great bulk of them bear both tubular and ray flowers in a single head. This may be single, or more commonly it is arranged in various kinds of clusters. Each head is surrounded at its base by one or more series of usually tightly overlapping bracts, incorrectly called a calyx by the unobservant. The Compositæ include over 900 genera and 11,000 species from all parts of the world. Most of them in America are herbs. Daisy, dandelion, dahlia, chrysanthemum, sunflower, boneset, chicory, lettuce, and scores of other examples could be cited, all herbs. In the tropics the Compositæ are more often trees and shrubs. The family contains many economic plants such as arnica, chamomile, artichokes, inula, and many others.
This all too brief account of the grouping of plants in families, and the sequence of these from the comparatively simple naked-seeded pines, through monocotyledons, the apetalous dicotyledons, followed by the polypetalous dicotyledons, and culminating in the Compositæ among the gamopetalous families, gives us merely a hint of what are the characters upon which plants are divided. While the details are necessarily omitted, the gradual development from naked-seeded plants, wholly at the mercy of the elements, up to those which are marvelously provided with contrivances to insure cross-fertilization, has been traced. Perhaps no other phase of botanical study offers such a rich opportunity as this, for upon the solution of some of the problems of plant classification depends the answer to many questions about the history of the earth and man’s ability to live on it. Certain of these plant families have lived on the earth hundreds of thousands of years before man first came. Others have apparently arisen comparatively recently. Many botanists believe that all the monocotyledons should be placed after the dicotyledons, as the latter may be a more ancient type than the former. How these different plant structures, some very ancient and others more recent, help to show us some of the history of the earth, will be treated, among many other evidences of a plant nature, in the chapter on “The History of the Plant Kingdom.”
CHAPTER V
USES OF PLANTS TO MAN
FOR perhaps the largest number of readers the chief value of plants is what they furnish in the way of food, clothing, fuel, and so forth, and from this standpoint alone the study of them is more than worth while. It is unnecessary here to enumerate all the thousand and one things that we get from plants, and no attempt will be made to do so in the following pages. But certain plants like wheat, corn, cotton, jute, rubber producers, and tobacco have so shaped the life of the people, so absolutely dictated the development of whole regions of the earth’s surface that their stories are part of the history of mankind. What our cotton fields of the South, the wheat and corn fields of the Middle West, the jute in India, and the coconut palm and sugar cane in the tropics have done to dictate the economic destiny of those regions is common knowledge. Hundreds of less important plants throughout the world contribute their quota to the huge debt that man owes to the plant world. Probably no other feature of plant life offers such attractions as the study of man’s uses of plants, which is known as Economic Botany, and for which our Government maintains a large staff of experts. Some of the publications of this bureau are textbooks of the greatest value to those who grow or import plants or their products. What that amounts to in the aggregate no one can readily estimate. It certainly exceeds all other commerce combined.
1. Foods
Those early ancestors of ours that roamed over northern and central Europe between the periods of ice invasion, which at times made all that country uninhabitable, tell us by the relics of them found in caves that agriculture was then unknown. Living mostly by the chase and on a few wild fruits picked from the forest these half-wild and savage people wandered wherever game was plentiful and the continental glacier would permit. But there came a day when one of these races began the cultivation of some of the wild plants about them and with that day dawned the real beginning of man’s use of plants. And with that day also these simplest of our ancestors stopped their wanderings in large part and became farmers, albeit very crude ones, as their primitive stone implements show. They did not give up the chase, but their collection into more or less permanent camps or villages began with their cultivation of plants. Just when this happened no one can say, but most estimates of the time since the last ice age indicate that it could not have been much less than forty thousand years ago. And considerably before this, and long before the use of metals by man, we find these stone implements of agriculture and the probable beginnings of that great reliance upon plant life which the modern world has carried to such tremendous lengths. Unfortunately we do not know what plants these “Men of the Old Stone Age” grew in their primitive gardens, and it is thousands of years after this, and after man’s discovery of the use of metals, that we know definitely what plants he grew and how he used them. Unquestionably some of the early uses of plants, such as dyes for the face or for “rock pictures” are very ancient and are found long before any sign of agriculture, but as food in the sense of being produced food rather than that gathered from the wild, there are only the faintest traces until, in the remains of the lake dwellers in Austria, a single grain of wheat was discovered. Their metal instruments showed them to have been familiar not only with this, but with other plants, and it is well to remember that these people lived far longer ago than our most ancient historical records such as the Egyptians or Chinese. Both the latter, so far as our oldest records of them show, were an agricultural people who had enormously developed man’s uses of plants as compared with the men of the stone or bronze ages, whose agriculture must perhaps forever be a secret of the past.
WHEAT
The discovery of the grain of wheat in the remains of the lake dwellers tells us some things about men’s travels even in those early days, for wheat is not a wild plant there and must have come to central Europe from a great distance. Researches upon the home and antiquity of wheat are not very definite, but its occurrence as a wild plant somewhere in Mesopotamia or the vicinity appears to be indicated. The Chinese grew it 2700 B.C. and the earliest Egyptians spoke of its origin with them as due to mythical personages such as Isis, Ceres, or Triptolemus. From its ancient and perhaps rather restricted home it has gone throughout the temperate parts of the earth and now forms perhaps the most important source of food. Although many different kinds of wheat are raised in different parts of the world most of them have been derived from one wild ancestor, Triticum sativum. Forms known as hard and soft wheat and dozens of others suited to different regions or market conditions have been developed by plant breeders. As the most important of all the cereals it has been much studied, and its cultivation in America is on such a tremendous scale that we furnish a large part of the world’s supply. Russia, Argentina, and the southern part of Australia also raise large quantities. The plant is a grass and the “seed” is really a grain or fruit in which the outer husk tightly incloses the true seed.
It were perhaps well to note here that popular stories about the germination of grains of wheat taken from Egyptian mummies are not true. Wheat and even corn are sometimes given to travelers, and it is taken from these ancient Egyptian tombs. But it was not put there by the early Egyptians, as the presence of corn proves only too well. For this cereal is an American plant unknown before Columbus and 1492. Arabs and others have recently inserted various seeds in these mummies, some of which undoubtedly have germinated—hence the fable. The early Egyptians did put seeds in their mummy cases, but none have ever germinated.