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1902] GAMETOPHYTES AND EMBRYO OF PODOCARPUS gi 
pollen grain, were found in material collected from the same 
tree on a single day. This does not necessarily imply any 
unusual rapidity of development, for pollen was being shed from 
this tree for more than a week. Asa matter of fact, however, 
the divisions in the grain, when once begun, follow each other 
in rapid succession, a fact also noted in the pollen of Pinus by 
Coulter and Chamberlain (1901). In the same cone undivided 
grains may be found at the top and three-celled ones at the base. 
It may be stated at once that there are three mitotic divisions in 
the pollen grain, forming two prothallial cells, a generative cell, 
and a tube nucleus. This noteworthy and rather unexpected 
behavior shows that in all essential points the pollen grains of 
Podocarpus and of the Abieteae are duplicates, and the peculiari- 
ties to be described below do not affect this fundamental agree- 
ment. 
It is interesting to note here a wtieuoe made by Schacht 
as long ago as 1860. Hesays: “ Podocarpus, dessen mannliche 
Blithe den Abietineen entspricht, hat auch dieselbe Form des 
Bliithenstaubs, der wahrschleinlich in derselben Weise seinen 
Pollenechlauch entwickelt.” The only other gymnosperm in 
which it is established that two prothallial cells are normally 
found in the pollen grain is Ginkgo, first figured by Schacht 
1860). In Ceratozamia longifolia Juranyi (1870) found three 
. small cells (presumably two prothallial and one generative) a 
ee Sometimes present in the pollen grain, although two was the — 
: _ ©ommoner number. In all other Cycadales investigated only 
_ One prothallial cell has been found. “Schacht found three small 
a in the pollen of Ephedra, while Juranyi (1882) figures | oo 
_ Varying number, in one ‘Case six nuclei being shown. In Taxus pee 
and the Cupresseae no prothallial cell has yet been discovered 
in the microspore, and there are none found in Taxodium. ee Se 
During all of its divisions the pollen grain of Podocarpus 1 co 
~~ with starch ( figs. 1-6), which disappears only just before — 
a. is shed. I know of no other gymnosperm in which 
. ai cl the case. The first division i is shown in fig. 7. AY 
a cell of the usual shape is cut off, but, as in other cases 
