290 BOTANICAL GAZETTE [October 



The second male nucleus disappears in tlie upper end of the egg 

 and^ as it disintegrates, minute cells appear, which are believed to be 

 the joint product of the chromatin of the second male nucleus and the 

 chromatin of some of the Jacket cells; these minute cells at least 

 foreshadow the endosperm of angiosperms, and may be called physio- 

 logical endosperm. 



The fusion nucleus gives rise to eight free nuclei, two to five of 

 which produce suspensors. 



Each functioning proembryo produces an embryo with a single 

 suspensor. 



Only one embryo reaches maturity. 



If moisture is supplied the seed does not rest. 



Six months elapse from the setting of the strobili to the ^' germina- 

 tion" of the seed. 



Ephedra must be considered as the most primitive of the 

 Gnetales. 



Note. — Since this paper was in type, a paper by Miss Berridge and Miss 

 Sani)y^° on £. distachya has appeared. 



They report the male nuclei as being inclosed in a common cytoplasmic 

 sheath and markedly unequal. The functional nucleus slips from this sheath, 

 but was not observed to function. Two kinds of embryos — normal and p.bnor- 

 mal — are described; the former being essentially as described for JS. trijurca; the 

 latter, if the interpretation of the authors is accepted, is unique among gymno- 

 sperms. The nuclei of the jacket cells divide amitotically, escape from the cells, 

 fuse in pairs, and produce proembryos. ^'In some cases the embryos are merely 

 enlarged jacket cells which project into the archtgonium." The writer has 

 repeatedly observed in E, trijurca appearances which at the first glance might be 

 interpreted as they are by these authors; but on careful examination and comparison 

 in several thousand ovules they were found to be proembryos formed in the usual 

 way. The ovule of Ephedra is so delicate that a slight pressure before fixation 

 is almost certain to result disastrously to the structures. 



The University of Chicago 



EXPLANATION OF PLATES XX-XXII 



All 



with 



one -half in reproduction. Abbreviations are: mu male nucleus which fuses 



the egg nucleus; Wa, male nucleus w^hich does not fuse with the egg nucleus; -y, 



ao BERi^rDGE, Ethel M., and Sanday, Elizabeth, Oogenesis and Embryogeny 

 in Ephedra distachya. New Phytologist 6:128-134, 167-174. pis, 2, J. 1907. 



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