THE EMBRYO OF CERATOZAMIA: A PHYSIOLOGICAL STUDY 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY III 



(with seven figures) 



Ceratozamia is a genus of cycads of the American tropics. Its 

 habit and habitat and the manner in which the ovules are shed shortly 

 after fertilization are described by Chamberlain (i) in his preliminary 

 note to the study of the reproductive structures. 



The embryo has only one cotyledon. This fact was observed by Van 

 Tieghem (2) as early as 1873 in a form which he considered a hybrid 

 between C. longijolia and C. mexicana, but which was probably pure C. 

 longijolia. In 1878 Warming (3) recorded the monocotyledonous condition 

 of the embryo of C. mexicana, adding that the cotyledon arises at one side 

 of the hypocotyl axis and little by little comes to surround it. 



Being engaged in an anatomical study of the seedling, the first observa- 

 tion I made was naturally upon this character. In every case in over one 



