Some of his information with regard to botany was far ahead of his time. He not only knew that the rings seen in the wood of the trunk of a tree represent its age, one ring for each year, but he also knew how to deduce from the differing thickness of the various rings the particular kind of season and how favorable it was for growth. In Italy moisture represents to a great extent the most important element in a favorable year for plant growth. Leonardo seems to have shown by the story of certain years in the past that when moisture was abundant the rings of the trees were thicker than they had been in other years. He pointed out, too, that the core of the trunk of a tree, the heart of the wood as we call it, was not in the centre of the tree as a rule, but always a little to one side because the tree had more sunlight and heat on one side and grew more in that direction. He pointed out too that when a tree is injured an abundance of sap is carried to that spot in order to bring about repair, and that these processes of repair always make a super-abundance of tissue, as if to overstrengthen a weaker part--hence the irregularities that are likely to exist on a tree where injuries have been inflicted. The sketches of dissections of flowers found in his notebooks show how well he anticipated many methods of study and details of knowledge in botany supposed to be much more modern. They have proved as great a surprise as his anatomical plates.
The professional botanists of this period have been very thoroughly reviewed by Professor Edward Lee Greene, Professor of Botany at the Catholic University and Associate in Botany in the United States National Museum, in his "Landmarks of Botanical History," which forms part of Volume LIV in the Smithsonian Miscellaneous Collections. He has called attention particularly to the work of the great German Fathers of modern botany during the late fifteenth and early sixteenth centuries. There are five of them who deserve a prominent place in the history of botany. Otho Brunfelsius (1464-1534), Leonhardus Fuchsius (1506-1566), Hieronymus Tragus (1498-1554), Euricius Cordus (1486-1535) and Valerius Cordus (1515-1544). The four first named represent two distinct [{376}] kinds of botanical work. Brunfels and Fuchs busy themselves almost wholly with medical botany. Their one idea was to describe plants that could be used in medicine or make special additions to the diet. Most of their plant descriptions are copied from older authors, some of them even the Greeks, but for practical purposes they sought to render the identification of medical plants more easy and certain by supplying pictures of them. There had been botanical pictures before but they were miserable as a rule, and both Brunfels and Fuchs greatly improved the representations. As Greene says "these two might worthily have been styled Fathers of Plant Iconography."
Books of botany must have been popular before this and indeed it was probably because of the ready sale of such works that Brunfels and Fuchs took up their elaboration of them. Their large picture books now made it possible for all sorts and conditions of men, lettered and illiterate, to identify some hundreds of useful plants; a thing which had never happened in the world before that day. They added little to scientific botany, however, but fortunately other men, Tragus and Valerius Cordus, laid serious scientific foundations for the true science of botany. Neither of these men wished to popularize botany so much as to make it possible for plants to be so described as to be readily identifiable by description. As Greene says "on Cordus' part it is unmistakable that there is a deliberate plan of creating a new phytography. Therefore and by study of the men and their books I think we shall perceive that in the Germany of the first half of the sixteenth century there were two fathers of plant iconography and two fathers of descriptive botany."
Greene can scarcely say too much of the work of young Cordus. He says (page 272): "To understand the exalted character of this genius it is only necessary to canvass what the youth had also attained to along other and different lines at the same time.
"In field work in Germany--for botany alone--not to speak of geology and mineralogy, in both of which he was, for his time, an expert--he had wrought out more results than had his older contemporaries, Brunfelsius, Tragus, and Fuchsius combined. In his repeated journeys to the great forests and [{377}] wildest mountain districts, it is estimated that he discovered several hundred new plants. Sprengel has given the Linnaean names of some twenty-five of these new discoveries of Cordus; and that is perhaps double or treble the number of novelties gathered in by the whole three above named; and they both were men of longer life and more or less extensive travel."
Greene re-echoes the praise of a contemporary in terms which show us that this young man, who lived less than thirty years, had all the qualities of a modern successful scientific investigator. Indeed that contemporary description is worth while having near one as a catalogue of qualities of the men who in every age succeed in science as a rule. It comes from Riffius' Preface to Cordus' "Annotations on Dioscorides":
"To the best possible education of an intellect naturally keen, there was united in him that happy temperament to which nothing is impossible, or even difficult of attainment. To these gifts he added a truly marvellous industry and assiduity in research; and above all, a most wonderfully retentive memory for everything he either saw in nature or read in books. In this he so greatly excelled as to be able to carry in mind in their entirety descriptions of things which he had not seen but was looking to find; thus having the descriptions always available whenever occasion called for the use of them."
Conrad Gesner at Zurich declared that the four books of Cordus are "truly extraordinary because of the accuracy with which the plants are described. A century and a half later, Tournefort named Valerius Cordus as having been the first of all men to excel in plant description. Haller, the distinguished botanist and historian in Linnaeus' time, credited Valerius Cordus with having been "the first to teach independence of the poor descriptions of the ancients and to describe plants anew." Greene says of him: "One sees that in all his descriptions the same attention is given to the morphology and also to the life history of the plant in as far as this is known to him. In his practice of describing each species, both morphologically and biologically, he is a herald of our late nineteenth and early twentieth century writers who now that we have the microscope give life histories with minuteness of detail before impossible."
Evidently Columbus' period gave birth to men as great in the investigation of plants and as ardent in their desires to get the last details of truth as were the geographers and the navigators of the time to reach the ends of the earth and be able to map it out. There was a great wind of the spirit of investigation abroad and everywhere there were magnificent results from it. This school of botany in Germany with Valerius Cordus as the climax of it, whose untimely death before thirty was indeed an irremediable loss to science, illustrates this very well.