352 



nearly' all llie stages sliidied. The cliromosoine pairs differ appreci- 

 ably in size. The vegetative cells of E. violaceo-petiolata exhibit a 

 peculiarity which seems to belong only to this subspecies and occurs 

 but very rarely in the vegetable liingdom. The normal number of 

 chromosomes (diploid) is here 12 (Fig. 3). This number, however, 

 was very seldom found. In almost e\'ery case the numbers found 

 were higher and invariably different, up to 100 and probably still 

 higher. Only in distinctly early prophases could the number 12 be 

 found with certainty, and in very late telophases, shortly before the 

 period of rest commences, this number is again nearly reached. In 

 this last stage the counting is a matter of great difl[iculty,,as the 

 nuclei are very small and the outline of the chromosomes indistinct. 

 Finally there is a third stage in which the normal number occurs, 

 namely, the stage of splitting and seperation of the chromosomes. 

 Occasionally, however, the number 12 was clearly seen. In all other 

 stages of division the chromosomes di\ide up into numerous chro- 

 matic particles (P'ig. 4). The longer the time is between the division 

 stage and the resting stage, the larger is this number. How the 

 transition from these stages and the metaphasic division-stage is 

 accomplished could not be investigated. 



The formation of the emhi'yosac takes place in all three elemen- 

 tary species mainly in the same way. One large right-angled sub- 

 epidermal cell immediately becomes an embryosac-motlier-cell, without 

 first forming a tapetal-cell. The emhryosac grows considerably in 

 size and the nucleus passes through a lengthy synapsis-stage. Finally 

 it divides into two daughter-nuclei which do not divide again directly, 

 but round off and like normal mitotic nuclei pass over into a res- 

 tiiig-stage. A cell-wall is formed, and for a short time the two 

 daughter-cells lie undivided. Then only does a second division take 

 place in the two cells. Frequently the micropylar cell degenerates 

 during this division; in other cases this takes place with the new- 

 formed products from it. This division of the micropylar daughter- 

 cell very often takes place in a transverse direction, whereas that 

 of the chalazal daughter-cell always takes about the same direction 

 as the first division of the embryosac-mother-cell. One of the four 

 grand-daughter- or tetrad-cells, that is situated nearest to thechalaza, 

 increases and becomes primary embryosac-cell. The other three tetrad- 

 cells have usually degenerated by now and meet closely over the 

 embryosac-cell. 



The development of the primary embryosac-cell to an embryosac 

 probably takes place according to the normal plan ; stages with 2 

 and 4 nuclei are frequently met witii. The nuclei lying near the 



