104 



angium, and that from these sixteen cells the final spores are 

 formed. The stage between the first spore cell and the sixteen 

 cells is directly comparable with the " division-period " in animal 

 maturation. The sixteen-cell stage (see next page) is the stage of 

 enlargement and of tetrad-formation and corresponds with the 

 "growth-period." Finally the "maturation-period " is recognized 

 by the two consecutive divisions of the sixteen cells to form the 

 sixty-four spores. 



As the maturation phenomena are so closely parallel in plants 

 and animals, it would be of advantage to have the corresponding 

 cells designated by analogous names. In some cases the present 

 botanical names are unwieldy and inappropriate. The " spore- 

 mother-cell " as a designation for the cells of the sixteen-cell stage 

 is incorrect as well as clumsy; for, if we consider the nuclei alone, 

 these cells do not give rise to the spores, but to the " mother-cells " 

 of the spores, and are therefore the " grandmother-cells " of the 

 spores. I propose, therefore, to use the term " primary sporocyte " 

 for the cells of the sixteen-cell stage, and " secondary sporocyte " 

 for cells of the thirty-two-cell stage. These terms are directly 

 analogous to " primary" and " secondary" "oocyte," and " sperma- 

 tocyte" in animal cells. The term " sporogonium," which in this 

 connection would be analogous to the term " oogonium " or " sper- 

 matogonium " is, unfortunately, already used in a different sense 

 in botanical nomenclature and 1 shall therefore designate the first 

 eight cells in spore formation as " archesporial cells" in accordance 

 with botanical usage. 



C. Observations. 



It is beyond the scope of this paper to describe in detail the 

 formation of the sporangium, with its annulus and tapetum, or 

 to describe the degeneration of the tapetal cells. Nor is it neces- 

 sary to give aminute account of the mitoses leading up to the 

 formation of the sixteen sporocytes. They all agree with the 

 division of the " archesporium " and the number of the chromo- 

 somes apparently remains the same, although they are so numer- 

 ous that it is impossible to give the absolute number. From care- 

 ful counting in several cases, I estimate the number to be between 

 one hundred and twenty and one hundred and thirty. 



The unicellular archesporium, which is destined to give rise to 



