KNOWLEDGE OF CRYPTOGAMOUS PLANTS. 251 



comprehensively arranged material. Botanists, liowever, gradually be- 

 came conscious that their system should not be only an arrangement of 

 plants according to certain arbitrary characteristics, but that their 

 essential peculiarities and natural relations among themselves must be 

 considered in their classification; in other words, that they must estab- 

 lish a natural system. Jussieu made the first successful attempt to 

 build up such a system. Among- the French, de Candolle, and among- 

 the English, Robert Brown, the two Hookers, and Lindley perfected it. 

 In Germany, and especially in Austria, it found its most perfect ex- 

 pression in our genial and renowned compatriot, Professor Stephan 

 Endlicher, with whom must be mentioned his friends and colleagues. 

 Professors Fenzl and linger, my highly-esteemed teachers. 



The change which the natural system produced in the direction of 

 botanical research, ever made it more necessary to study out the laws 

 of the growth, foruuxtion, reproduction, and propagation of plants; to 

 find out with accuracy the relations existing- between their dilferent 

 organs, and to investigate the origin and development of the whole 

 plant and its separate parts, down to the most elementary organisms. 

 Thus morphology became a separate branch of botany through the 

 endeavors of Robert Brown, Roper, Alexander Braun, Schleideu, 

 Schacht, Hofmeister, and others. 



Morphological studies naturally led to a more accurate consideration 

 of the structure and the processes of plant-life. The microscope had 

 meanwhile been greatly improved, and many botanists took up this 

 branch with i)redilection. In this way the anatomy and physiology of 

 plants reached a point, through the excellent labors of Hugo von Mohl, 

 linger, Kiigeli, Schachfe, and others, which had not before been thought 

 possible. 



Excursions to all parts of the world were undertaken by courageous 

 investigators, who not only enriched the science with a great many new 

 forms, but rendered it possible to determine the laws of the distribution 

 of plants over the whole earth; so that Alexander von Humboldt was 

 enabled to produce a masterly- sketch of botanical geography. 



In a measure, as mutual intercourse was facilitated, more life was in- 

 fused into scientific research ; a great number of scientific societies 

 and periodicals were established where the results of investigations 

 were deposited. So many of these publications appear now that it is 

 extremely dilficult, if not im])0ssible, to examine them all. During this 

 great progress of botany in generiU, the cryptogams were not neglected. 

 Indeed, many of the most thorough scholars made a specialty of 

 these simplest of organisms. The in)i)ortant discoveries became so 

 numerous in this department that it was entirely revolutionized. 

 I will endeavor to present to you a condensed view of the most im- 

 portant achievements. For this purpose the material has been divided 

 into five grou))s : algte, lichens, fungi, mosses, and ferns. In each of 



