1915] HUTCHINSON—MALE GAMETOPHYTE OF PICEA 291 
the microspore just prior to germination”’ (15). When two evan- 
escent cells are cut off, these divisions take place before the increase 
in size. They follow one another in rapid succession; all stages 
of the first two primary divisions are to be found in the same spo- 
rangium. A resting period, that is, a period during which mitosis 
ceases, but during which there is a great increase in size and ap- 
parently in food supply, precedes the formation of the functioning 
antheridial cell, whether it be the first, second, or third primary 
derivative (figs. D, H, L, O, S and 30, 38, 44, 45). Since this last 
primary division and the secondary division to form the sperma- 
togenous cell and the sister sterile cell are to be found in the same 
sporangium, it is evident that they are closely consecutive. The 
complete development is extremely rapid; on May 3 only one- 
celled stages were to be found, while on May 6, or sooner, the 
pollination stage had been reached. Trees on a sunny hillside 
shed the pollen at once; others retained it for ten days without 
further development. The functioning antheridial cell is imbedded 
in the cytoplasm of the primary cell, as shown above, and an in- 
crease in the size of the pollen grain precedes mitosis of the former 
cell. Evidently nutrition is a factor in determining the fate of 
an antheridial cell; in other words, whether the first, second, or 
third shall function as such. 
Degeneration 
In lenticular cells which contain a minimum of cytoplasm sur- 
rounding the nucleus, the latter does not pass out of telophase 
(fig. 26); the chromosomes contract, become globular, and finally 
disintegrate as irregularly granular masses (figs. 20, 21, 43), or 
accumulate at the periphery of the nucleus, giving it a vaginated 
appearance (fig. 45). When these cells collapse, double darkly- 
Stained bands appear in cross-section. In Picea canadensis the 
intine does not imbed these degenerating cells. The first primary 
wall elongates as the pollen grain increases in diameter (figs. 37, 
38, 50, 51); often it has the appearance of a third wall (fig. 50) 
which is attached to the intine near the origin of the wings. The 
disintegrating cell contents remain within the original walls; the 
latter meanwhile become elongated and thickened. 
