S4 Dr. H. Karsten on the Sexual Life of 



Madeira on Gladiolus segetum, advocated the opinion of Amici 

 and Mohl with reference to the production of the embryo, as 

 exclusively correct. 



Not one of these anatomists called in question the theory 

 of the sexual origin of plants put forward by Camerarius and 

 Linuseus. Their views differed only on the question whether 

 the rudiments of the new being were commenced exclusively 

 within the embryo-sac^ or exclusively within the pollen- tube, or 

 by the united action of the two organs, after the manner of the 

 conjugation of the Confervas. The majority of botanists certainly 

 incline towards the opinion that the basis of the young embryo 

 is furnished solely by the gertninal vesicles contained within the 

 embryo-sac, and never by the pollen-cell, whose contents serve 

 no other purpose than that of its fructification. Moreover, the 

 plants which Linnaeus cautiously named Cryptogamia have been 

 of late years for the most part proved to be Phauerogamia ; for, 

 in 1848, Suminski, by observations first made on the thalli of 

 Ferns, showed that those organs which Hedwig, in the case of 

 Mosses, had rightly intimated to be anthers and pistils, actually 

 performed the functions of such structures in Ferns ; and since 

 then, in 1850, I sent from Venezuela to Prof. Ehrenberg, as 

 Secretary of the Berlin Academy, the first part of the history of 

 the fructification of an Alga, which confirmed the idea of Nageli 

 respecting the sexual nature of the two sorts of stalked branches 

 remarked by Vaucher. These two observations together made 

 us acquainted with the extreme forms of the fructifying organs 

 among the Cryptogamia : namely, in the one case the motory 

 apparatus, which is to be compared to the extine of the pollen, 

 is developed pre-eminently ; in the other case the cell, which is 

 comparable with the intiue of the pollen, attains the maximum 

 development. Still, in both cases, the latter is always present as 

 the special fructifying organ — overlooked, it is true, by many 

 observers, either because, in cellular Cryptogamia, they considered 

 it to be an integi-al part of the spiral fibres producing the mo- 

 tions, or because, in the vascular Cryptogamia, they examined 

 spiral fibres from which the fructifying cells were torn off. 



The conjugation of Spirogyra, described by Vaucher as the 

 simplest form of a reproductive process, is indeed still so re- 

 garded by the majority of botanists at the present day, and my 

 researches on Vaucheria show it to be so in the clearest manner. 

 In some cases, the impregnation of the naked archegonium takes 

 place by means of a free spherical cell (PI. IX. A. fig. 23 a), which 

 escapes from the open extremity of the antheridium within 

 which it was produced, adheres to the archegonium, and after 

 a time coalesces with it, so that the two united lay the founda- 

 tion for the new individual . However, I more frequently observed 



