426 BOTANICAL GAZETTE [JUNE 
Fic. 36. Spore mother cell stage; tapetum developed. 
F1G. 37. Synapsis stage. 
Fic. 38. Stages following synapsis. 
F1G. 39. Division into tetrads. 
Fics. 40, 41. Formation of microspores. 
Fics. 42-46. Irregular division into five and six spores instead of tetrads. 
Figs. 47-50. Development of pollen grains and division of nucleus into a 
larger vegetative and a smaller lenticular generative nucleus. 
Fic. 52. Diagram of pistil showing relation of stigmatic surface, path of 
pollen through placenta, and connection with channel in neck of nucellus 
leading to embryo sac. 
