1015] 



HUTCHINSON— MALE GAMETOPIIYTE OF PICEA 



nature of the first primary division. When the primary derivative 

 is small and lenticular, it rapidly degenerates (figs. A-I and 20-26 

 etc.); when the division is median or nearly so, each of the two 

 cells formed has the power of repeated division, giving rise to a 



Figs. A-U. — A diagram to illustrate five types of development in male game- 

 tophytes of Picea canadensis: P, primary cell; a', a", a'", the first, second, and 

 third (potentially) antheridial cells; s, spermatogenous cell; st, sterile cell; the 

 dotted lines indicate origin and sequence; relative size is also shown; figs. A-E, three 

 primary divisions, first and second cells cut off evanescent, third by a secondary 

 division produces a spermatogenous and a sterile cell ; figs. F-I, two primary divisions, 

 second cell cut off from primary cell functions as antheridial; figs. K-M, first primary 

 derivative functions as antheridial cell; figs. N-Q, two primary divisions give rise 

 to two antheridial cells, repeated divisions of the first produce four free nuclei; figs. 

 R-U, primary cell divides to form sister primary cells, each of which produces an 

 antheridial group, a bi-antheridial gametophyte. 



