herbaria, a significance being given to the word which it has now lost. It soon became painfully evident that very good and conscientious descriptions, even when accompanied by accurate plates, were yet not adequate to express all those delicate details which the living plant showed. So some of the authors found a way to keep the plants they had described, at first for their own reference, and for this purpose dried them carefully, glued them on sheets of paper, and put the name on this paper. Preserved in this way and arranged alphabetically for easy reference, these specimens formed a supplementary confirmation of their descriptions which was readily accessible. This was what we now call a herbarium—in other words, a collection of well-preserved, carefully named dry plants. If the description of an author who had a collection of this sort was called in question, it was an easy thing for him to send his original plant to some third botanist, who could decide whether he was right. Afterward it was recognized by those who described new plants that it would be of great importance to them if they could have the originals of the descriptions of their fellow-botanists. So a system of interchange of originals arose, which is now carried on between botanists all over the world. A trained and competent botanist who finds an opportunity to study the flora of regions which are little known may by this means become possessed of all the most instructive and remarkable plants that are known to science.
So a modern botanist no longer collects, as was formerly done, only one or two samples of every plant, but one or two hundred—of rare species often two thousand—because every specimen he has will enable him to obtain some new one in exchange.
The difficulties of collecting in the present time may be estimated from this. To collect four thousand plants in a tropical climate means not only to find, dry, and name these under the most unfavorable conditions, but to prepare perhaps forty thousand, all the duplicate specimens being used in exchange.
For a long while plants were named by any word which took the fancy of its author, and were arranged in the alphabetical order of the names. Soon, however, it was found that a better disposition was desirable, as nobody could look over such extensive alphabetically arranged collections, and students began to assort the plants in such a way that those which had certain characteristics in common were grouped in classes. So, for example, all kinds of grasses, all kinds of trees, all kinds of shrubs were put together, etc. Such a beginning of classification and unconscious recognition of relationship was begun by Lobelius and Bauhin, extended by Cæsalpin, and completed by Linnæus.
