INTRODUCTION. 



7 



As might be expected, it was soon discovered tbat two 

 or more plants had characters and virtues in common, 

 which led to their being classed in accordance with their 

 relative appearance to each other ; thus came grass, herbs, 

 and trees. The increasing knowledge of man in time led 

 to more defined systems of classification, and the first 

 book extant specially treating of plants is that of Theo- 

 phrastus, written three hundred and twenty-four years 

 before the Christian era. In that work about seven hun- 

 dred plants are described, of which about one-half have 

 been identified by modern botanists as natives chiefly of 

 Greece, the descriptions of the other half being too vague 

 to admit of their identification. He was followed by 

 others, now called ancient writers, to describe whose 

 works would form a volume of itself. The classification 

 of these writers was in most cases by dividing the plants 

 into families, according to their likeness to each other, 

 places of growth, or virtues. This system was followed 

 by early writers in this country, such as Turner and 

 Gerard in their herbals — the first published in 1551, and 

 the latter, a thick folio volume, in 1597 — in which the 

 descriptions and medical virtues of plants for the cure of 

 all complaints are quaintly set forth. At that period 

 those who collected and cultivated herbs were called 

 herbalists, and as they were acquainted with their virtues 

 were looked upon as sages in the healing art. 



In the course of time, a knowledge of plants became a 

 necessary part in the education of medical students, and 

 on the establishment of colleges and universities, profes- 

 sors were appointed, whose successive teaching and writings 

 led to the closer study of plants till it became a special 

 science known as botany. It was not, however, until the 

 beginning of the last century that botany began to assume 



