378 BOTANICAL GAZETTE [November 



that described above for Phajus, Corallorhiza, and Broughtonia. 

 In each of the other two cases the antipodal nuclei had also divided, 

 forming an 8-nucleate sac (fig. 44). In none of these sacs were 

 walls observed separating the nuclei at either end. 



Since no walls are present at the 4-nucleate stage, the nuclei are 

 free to wander about through the sac (fig. 45). They were seen in 

 all positions, but sooner or later they may all fuse to form one 

 large nucleus. The most common course followed is that repre- 

 sented in figs. 46-48; the nuclei near each end of the sac fuse and 

 the resulting fusion nuclei do the same. Often all four fuse at once; 

 sometimes only two fuse ; and in many cases degeneration sets in 

 before any fusions have occurred. 



Apparently the pollen tube may enter the sac and discharge 

 its two male nuclei at any of these stages. In fig. 49 it has extended 

 to an unusual distance into a sac like that shown in fig. 47> an( * m 

 fig. 50 the male nuclei have been- discharged into a sac containing 

 three nuclei in the central region. As far as could be determined, 

 no nucleus is set apart as the egg. The nuclei all lie in a group for 

 a time, and when disorganization does not occur at once they may 

 become fused (figs. 51-53). The large nucleus which results was 

 not observed to carry the development any farther. 



In the material sectioned embryos proved to be exceedingly 

 scarce, and this condition is undoubtedly connected with the irregu- 

 larity and lack of organization shown by the embryo sac. The 

 two-celled proembryo in fig. 54 has evidently formed in a 6 or 8- 

 nucleate sac, as beside the pollen tube there are in the micropylar 

 end two disorganizing nuclei, probably synergids, and in the chalazal 

 region a partially fused and degenerating group made up of at 

 least three. The next few divisions in the proembryo are transverse 

 (%• 55), so that in its early stages it is filamentous, as in Eptden- 

 drum. Meanwhile the placental tissue develops rapidly from all 

 sides, completely filling the cavity of the ovary, and the few pro- 

 embryos found were lying in the small intervening crevices. 



It is not unlikely that the great irregularity shown by Bletia as 

 here reported may be due in part to the somewhat artificial con- 

 ditions under which the plant grew in the greenhouse. 



