Botany

Botany is the scientific study of plants. While early humans were very knowledgeable about identifying harmful and beneficial plants, the ancient Greeks were the first to study plants scientifically (or for the sake of gaining knowledge rather than any practical purpose). The study of plants greatly expanded with the seventeenth-century invention of the microscope and today, modern botany uses a whole range of tools that investigate plants at their genetic level.

Plants are multicelled organisms that live by making their own food using the process of photosynthesis to harness the energy of sunlight and convert it into food. Plants are essential to all living things since they provide food, oxygen, energy, and even wood. Since early humans were hunter-gatherers before they learned how to farm, it was especially important to know which plants were good to eat and which were not. Some plants were sometimes found to have medical uses. Until the Greeks studied plants in the fourth century, knowledge of plants consisted primarily of the following types of practical information—which plants were safe, which were harmful, and which were good to cure illness.

THEOPHRASTUS CONSIDERED THE FOUNDER OF BOTANY

The Greek scholar Theophrastus (c.372–c.287 b.c.) began to study plants as life-forms worthy of study by themselves rather than sources of food or drugs. His work, titled Enquiry into Plants, survives today and has earned him the title "founder of botany." In this work he studied a wide range of plants and discussed seeds, budding, and the effects of disease

and weather. He also attempted a classification of plants and described their different parts. Following Theophrastus, other Greeks and Romans were more interested in the practical aspects of plants and most books written were "herbals" or works that contained mainly medicinal (and sometimes mythical) information on plants. The tradition of herbals, which stressed plants that were useful to people, continued throughout medieval times and the Renaissance.

OTHERS EXPAND ON THEOPHRASTUS'S WORK

By the middle of the sixteenth century, the scientific tradition begun by Theophrastus was revived in Germany as several naturalists began to produce botanical books that were based on facts rather than on the elaborate and sometimes fantastic claims of the herbals. These naturalists also began to investigate plant anatomy (the structure or parts of plants) and plant physiology (the internal life processes that take place). This scientific tradition was reinforced in the next century by the invention of the microscope, which allowed a better view of a plant's minute parts. By the end of the seventeenth century, plant anatomy was being studied seriously and many correct scientific discoveries were being made. In 1682, the English physician Nehemiah Grew (1641–1712) published The Anatomy of Plants in which he displayed eighty-three full-page plates of microscopic sections of plant stems and roots. Grew was the first to state that flowers contained a plant's sexual reproductive organs. His work and that of others led to the landmark work of the Swedish clergyman and naturalist, Carolus Linnaeus (1707–1778). After traveling through much of Europe studying plants, Linnaeus published in 1735 his System of Nature in which he created the modern form of systematic classification known as the binomial (two name) system. The first name he used was the genus, or the type of group, to which they belonged. This was followed by the species, or the particular name. His system soon became useful in classifying all living things. Following Linnaeus, botanists became increasingly specialized and nineteenth-century botany became best known for its discovery of photosynthesis and of the cellular structure of plants. By 1900, the earlier work of the Austrian monk Gregor Mendel (1822–1884), in which he worked out the actual laws of inheritance based on his work breeding pea plants, became well known and modern botany truly began.

Today, the study of botany has many interconnected branches. The major areas of investigation are plant anatomy or the study of the internal arrangement of plant parts; plant physiology or the processes (like photosynthesis) that take place inside a plant; plant morphology or the external or visible arrangement of a plant's parts; plant taxonomy or the identification and classification of plants; plant cytology or the study of plant cells; plant genetics or the study of plant inheritance; plant ecology or the study of a plant's relationship to its surroundings; plant paleobotany or the study of fossil plants; dendochronology or tree-ring dating; and ethnobotany or the relations between humans and plants (especially the identification of plants with medical properties).

THEOPHRASTUS

Greek botanist Theophrastus (327 b.c.–287 b.c.) is considered the father of botany, the scientific study of plants. He was the first to study plants solely for their own sake and not just to learn how they might be put to some practical use. Although few of his writings remain, what did survive became the principle source of botanical information for centuries.

Theophrastus was born on the Greek island of Lesbos and was lucky to study as a very young man with the great Greek philosopher, Plato (c.427 b.c.–c.347 b.c.). After Plato's death, Theophrastus met and became a lifelong friend of the second great philosopher of the ancient world, Aristotle (384 b.c.–322 b.c.). In fact, it was Aristotle who gave him his nickname "Theophrastus," meaning "divine speech." Aristotle had founded a school called the Lyceum which Theophrastus took over after Aristotle's retirement. Under Theophrastus's leadership, the school reached its highest point. There, he carried on Artistotle's teachings in biology, although he concentrated on the study of plants (botany), where Aristotle had specialized in the study of animals (zoology).

Although Theophrastus is believed to have written a great deal on many different subjects, only a small portion of his botanical work survived. In these works, he covered every major aspect of plants—their description, classification, and distribution as well as how plants propagate (reproduce). Significantly, he described the formation of the plant in the seed as being like the fetus of an animal, something produced by it but not a part of it. He identified and grouped more than five hundred species and varieties of plants from those he knew, as well as those from neighboring lands. He classified plants into trees, shrubs, undershrubs, and herbs and developed a way of naming plants based on their external and internal parts, which he called organs and tissues. He also described sexual reproduction in flowering plants, as well as seed germination (when a seed starts to grow and puts out a root) and development. Although the real function of pollen (dustlike grains that contain the plant's male sex cells) was not understood, he wrote detailed descriptions of how to pollinate certain fruit-bearing trees. His knowledge of plants was such that he knew that some flowers bear petals while others do not, and that there were major differences in the seed structure of flowering plants (called angiosperms) and cone-bearing trees (called gymnosperms). In fact, he is credited with inventing the term "gymnosperm" which in Greek means "naked seed." Finally, he described how Greek farmers used certain bean crops to enrich the soil. Today, farmers know that important nitrates (salts from nitric acid) are formed by bacteria that live on the roots of these bean plants, and that they add important nitrogen (a nonmetalic element) to the soil.

Theophrastus is rightly considered to be the founder of botany. Unlike many who followed him, his plant study was focused on learning about plants not for their practical uses (which are many and important), but from a purely scientific aspect, simply in order to learn more about them. His one surviving botanical work contains all the essentials of what today is considered scientific botany. He observed, collected, and systematized his botanical information, and wrote in a clear and accurate manner. Although missing from his work are all of the fabulous folk tales that surrounded plant lore, he brought a scientific mentality to the study of plants. In many ways, Theophrastus was more modern than anyone who followed him for the next two thousand years.

[See alsoPlant Anatomy; Plant Hormones; Plant Pathology; Plant Reproduction; Plants ]