1904] LAND—EPHEDRA TRIFURCA 7 
cell and the tube nucleus (fig. 20). The tube nucleus, although 
lying in close proximity to the wall of the microspore, does not become 
flattened as do the prothallial cells. In all preparations examined 
there seems to be no break in the cytoplasm surrounding the tube 
nucleus and the second prothallial cell (figs. 20-22), nor is a wall 
laid down between the tube nucleus and the primary spermatogenous 
cell. The primary spermatogenous cell—or generative cell—lies in 
a mass of cytoplasm differentiated from the surrounding cytoplasm 
by a slightly denser zone (figs. 20, 21). This condition of affairs is 
doubtless comparable to that of the generative cell of angiosperms, 
where there is a well-defined Hautschicht, on the outside of which 
food material is conspicuous. The primary spermatogenous cell 
dividing (fig. 21) gives rise to the stalk cell and the body cell, both 
of which lie within the cytoplasmic ring previously mentioned as 
surrounding the primary spermatogenous cell. The male gameto- 
phyte at this time (April 1, 1903) contains five nuclei: two prothallial 
cells, tube nucleus, stalk cell, and body cell. The microspore will 
be shed ten to fifteen days later. 
The time periods in the development of the strobilus and male 
gametophyte are as follows: The strobilus appeared the previous 
season; on December 20, 1902, the group of cells which gives rise to 
the staminate flower is apparent, but the “perianth” is not yet visible; 
January 27, 1903, the “perianth” is well along and the primordia 
of the sporangia are clearly apparent; February 10, the primary 
wall cells are dividing; by February 15 many sporangia have mother- 
cells in the resting condition; one month later (March 15) the reduc- 
tion division takes place; by April 1 the spores are mature, and about 
April 15 the pollen is shed. These records are for one season only, 
and the periods may be expected to vary somewhat in other seasons, 
the variations being of course dependent on various external factors. 
It appears that Jaccard never saw the prothallial cells, for he 
says that at maturity the pollen grain contains three nuclei: “a 
large central nucleus representing the antheridial cell of Belajeff and of 
Strasburger; and two vegetative polar nuclei, of which one is the tube 
nucleus (noyau du tube pollinique, Pollenschlauchkern), and the other 
homologous with the Stielzelle of the German authors.” So, putting 
' this into present terminology, what he saw at the shedding of the pollen 
