6 



INTRODUCTION TO EMBRYOLOGY OF ANGIOSPERMS 



Discovery of the True Relation between the Pollen Tube and the 

 Embryo. In spite of Schleiden's criticism, Amici continued further 

 work on the subject. In 1847 he produced decisive evidence (Fig. 3) 

 to show that in Orchis (which he found to be specially suited for such 

 studies), a body, the germinal vesicle, was already present inside the 

 embryo sac before the arrival of the pollen tube, and that it was 

 this vesicle which gave rise to the embryo, stimulated no doubt by 

 the presence of the pollen tube. 



B C D E 



Fig. 3. Development of ovule and embryo in Orchis. Note pollen tube in C 

 and D and suspensor haustorium in E. {After Amici, 1847.) 



Support for Amici 's views now came forward from other quarters. 

 In a famous document, entitled "Die Entstehung des Embryo der 

 Phanerogamen," consisting of 89 quarto pages and 14 copper plates 

 with no fewer than 429 figures, Wilhelm Hofmeister (1849) published 

 his observations on 38 species belonging to 19 genera and showed that 

 in every case the embryo originated from a preexisting cell in the 

 embryo sac and not from the pollen tube. He described his obser- 

 vations in such a clear and dignified manner that the}' immediately 

 carried conviction and were soon confirmed by other workers from 



