2co Morphology and Systematic Botany under [BOOK i. 



embryo on the other, and their significance in the history of 

 development, were brought out clearly by Hofmeister's investi- 

 gation, while the exactness of his method rendered lengthy 

 discussions on the subject unnecessary. With these embryo- 

 logical processes, especially those of the Rhizocarps and 

 Selaginellae, in which the presence of two kinds of spores was 

 now for the first time correctly interpreted, Hofmeister com- 

 pared the embryology of the Conifers, and by their aid that 

 of the Angiosperms also. 



The results of the investigations published in the ' Verglei- 

 chende Untersuchungen ' in 1849 and 1851 were magnificent 

 beyond all that has been achieved before or since in the domain 

 of descriptive botany ; the merit of the many valuable particu- 

 lars, shedding new light on the most diverse problems of the 

 cell-theory and of morphology, was lost in the splendour of the 

 total result, which the perspicuity of each separate description 

 revealed to the reader before he came to the conclusion of the 

 work, and there a few words in plain and simple style gave a 

 summary of the whole. Briefly to describe this result in all its 

 importance for botanical science is a difficult task ; the idea of 

 what is meant by the development of a plant was suddenly and 

 completely changed; the intimate connection between such 

 different organisms as the Liverworts, the Mosses, the Ferns, 

 the Equisetaceae, the Rhizocarps, the Selaginellae, the Coni- 

 fers, the Monocotyledons, and Dicotyledons could now be 

 surveyed in all its relations with a distinctness never before 

 attained. Alternation of generations, lately shown to exist 

 though in quite different forms in the animal kingdom, was 

 proved to be the highest law of development, and to reign 

 according to a simple scheme throughout the whole long series 

 of these extremely different plants. It appeared most clearly 

 in the Ferns and Mosses, though at the same time with a 

 certain difference in each ; in the Ferns and allied Cryptogams 

 a small inconspicuous body grows out of the asexually produced 

 spore, and immediately produces the sexual organs ; from the 



