CONIFERALES (PINACEAE) 



243 



In the case of Pinus Laricio (in Chicago), about the first of May 

 the mother cells are found in various stages of division, the sporan- 

 gium usually having passed the winter in the mother cell stage or in a 

 late stage of the sporogenous tissue. The divisions do not appear 



267 



268 269 



Figs. 266-269. — Winter condition of microsporangia: fig. 266, Pinus Laricio on 

 October i; fig. 267, the same on January 3; fig. 268, the same on April 4, showing 

 synapsis; while fig. 267 is probably in the mother cell stage, it is certain that sporo- 

 genous divisions sometimes occur in the spring; fig. 269, Taxus canadensis on Octo- 

 ber I, showing mother cell stage. — After Chamberlain (48). 



to be simultaneous as among angiosperms, for in the same sporangium 

 some mother cells are preparing for the first division, others contain 

 completed tetrads, and others represent every stage between (fig. 301). 

 In the same sporangium, also, the division may be simultaneous or 



