Miyake, The development of the gatnetophytes etc. 15 



Strasburg- er (1884) has noticed the starch-sheath around 

 the fusiiig- nuclei of Juniperus and expressed a surprise at the 

 sudden appearance of starch, as he has not found any starch in 

 the sperni-cell, while the polleu-tube contains very little starch at 

 the time of fertilization. Later students of the Cupressineae 

 (Lawson, 1907; Noren, 1907) have also observed the presenee 

 of the starch-sheath, except Land (1902) who makes no mention 

 about it in Tltuja. The presenee of starch in the sperm-cells 

 were mentioned by Noren in Juniperus and by Lawson in 

 Libocedrus. Taxodium, Cryptomeria and Curminghamia have then 

 these Points in common with the C^upressineae. 



The fusing nuclei are usually found at the center of the eg'g, 

 occupying the cavity of the vacuole, into which they have probably 

 dropped in after both nuclei came in contact. They may not fill 

 up the entire space of the vacuole, and there is offen a Space left 

 between them and the rest of the egg-cytoplasm (figs. 89, 113). 

 This Space is, however, gradually filled up by the surrounding 

 cytoplasm, and almost disappear at the time of the first spindle- 

 formation. 



The outline of the female and male nuclei remains distinct 

 until the fusing nuclei prepare themselves for division. It has been 

 reported that in Taxodium (Coker, 1903) and Taxus (Jäger, 

 1899) the fertilized nucleus passes down to the base of the Q:gg 

 before the first division occurs. This is evidently not the case in 

 Cunniughamia, for the first division-figure was always found at or 

 near the center of the q^^, just about the point where the fer- 

 tilized nucleus is usually located (fig. 114). Most investigators of 

 the Coniferae agree that the first division of the fertilized nucleus 

 occurs near the center of the e^^. So it was found by Lawson 

 to be the case in Cryptomeria and several other members of the 

 Cupressineae. Arnoldi (1900), on the other band, states that in 

 Sequoia the first division takes place at the base of the Qg^, but 

 the fact was not confirmed by Lawson (1904a). 



Embryo-formation. 



The fertilized nucleus soon prepares for division, while the 

 outline of each sexual nuclei is still dislinct. The nuclear niem- 

 brane becomes indistinct and the spindle originates at the point 

 where the walls of two nuclei meet. The process of division does 

 not seem to diifer much from that observed in other Conifers. 

 Miss Ferguson (1901, 1904) made a very minute study of the 

 division in Pinus and the results of her study can, in the main, 

 be also applied to Cmminglmmia. An early stage in the spindle- 

 formation of Cunniiujhamia is shown in fig. 91 which resembles 

 Miss Ferguson's (1901) fig. 56 with the exception that the latter 

 has no starch-sheath. The sindle is intra-nuclear and seems to 

 originate as a niultipolar structure. The chromosomes are found 

 in two groups and each group has evidently derived from one of 

 the sexual nuclei. 



