lopment of tlie ovule, lias regarded tliings. This pseudo- 

 embryo-sac remains in existence during the further deve- 

 lopmynt of the ovule to the seed, and is only compressed 

 more or less in some cases by the large increase in size 

 of the cells of the Inner integument, which has already 

 been dealt with abovc. When the embryo begins to develop 

 it grows out Into this pseudo embryo-sac, in the same 

 way as would happen with a true embryo-sac (fig. 11). 



We may now pass on to consider the fate of the spore 

 mother-cell. At a certain period its nucleus shows a clcar 

 synapsis stage. In the division, which follows this, the réduc- 

 tion of the number of chromosomes therefore problably 

 takes place. The fixation was not sufficient to allow one 

 to conclude with certainty that a hetero-typic division of 

 the nucleus occurs (the nuclei are moreover extremely 

 minute) ; such observations as were made, leave very little 

 doubt, however, when considered in connection with the pre- 

 ceding synapsis, that the haploid génération begins hère. This 

 nuclear division is followed by a cell division and the forma- 

 tion of a dividing wall (fig. 3, 4). The upper of the two cells, 

 which are thus formed, gradually dégénérâtes and becomes 

 more and more flattened by compression; remnants of it 

 may nevertheless still be observed for a long time (fig. 5, 

 7, 8, 14). In some cases the nucleus of this cell divides 

 once more, in a plane perpendicular to that of the pré- 

 viens division, so that the equatorial plane of the second 

 division is in the longitudinal direction, with respect to 

 the ovule (fig. 5, S). Perhaps this division also takes place 

 in other cases, in which the two nuclei cannot be seen on 

 account of the unfavourable direction of the section and 



1) E II g. W a r m i n g-. Familien Podostemaceae. II. Afhandling 

 Kgl. Danske Vidensk. Selsk. Skr. 61e Raekke, naturv. og math. 

 Afd. 2det Ed. III. K)ôbenhavn, 1882. Compare e.g. p. 65 (107). 



