I 

 I 



FERTILIZATION AND EMBRYOGENY IN EPHEDRA 



TRIFURCA^ 



FROM THE HULL BOTANICAL LABOEATORY 



W. J. G. Land 



(with PLATES XX-XXIl)' 



Little attention has been given to the fertilization and embryogeny 

 of Ephedra, the only accounts being those of Strasburger and 

 Jaccard. In 1872 StRxVSburger,* studying E. altissima^ described 

 and figured unfertilized eggs and four stages of the embryo immediately 



and 



In 1876 he described^ a 



series of stages in E. aUissima from the central cell of the archegonium 

 to the formation of suspensors. He noted the penetration of the 

 pollen tube, which, he says, reaches the egg through a canal formed 

 by the breaking-down of the neck cells of the archegonium- Fertili- 

 zation was not obsenxd, but several stages of the proembr}^o were 

 noted. Usually three to eight proembryos are formed and arranged 

 in a row down the middle of the ecfor. He calls attention to what he 



considers an abnormal condition, in which the cytoplasm of the egg 

 is pierced through by irregular tortuous channels supported through- 

 out their length by kinoplasmic fibers. These channels extend around 

 and finally inclose a portion of the egg cytoplasm together with a 

 single nucleus. He thinks these channels result from the activities 

 of this single nucleus which is finally inclosed. The breaking-out 

 of the suspensors from the archegonia was noted. His third account,-* 

 published in 1879, deals at some length with the embrj^ogeny of E. 

 campylopoda, but adds little to the results obtained from E. altissima. 

 In 1894 Jaccard/' studying E. helvetica, observed the pollen tube 



* Read before the Botanical Society of America, December 1906; abstract pub- 

 lished in Science N. S. 25:282, 283. 1907. 



^ Strasburger, E., Die Coniferen und die Gnetaceen, 1872. 



3 Strasburger, E., Ueber Zellbildung und Zellteilung. 1876. 



^ Strasburger, E., Die Angiospermen und die G}Tnnospermen. 1879, 



5 Jaccard, P., Recherches embryologiques sur Y Ephedra helvetica. Inaugural 

 Dissertation. Lausanne, 1894, 



273] 



[Botanical Gazette, vol. 44 



